Program 1:

/* Write a Java Program to input 10 numbers into an array and print them out. */
import java.util.*;
public class Program1
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] arr = new int[10];
System.out.println(“Enter 10 integers: “);
for(int i=0; i<10; i++)
{
arr[i] = key.nextInt();
}
System.out.println(“The integers are: “);
for(int j=0; j<10; j++)
{
System.out.print(arr[j] + “, “);
}
}
}

Variable Listing:

Variable Datatype Description

arr int[] to store 10 integer elements

i int to cycle through every index of the array (for input)

j int to cycle through every index of the array (for output)

Program 2:
/* Write a Java Program to input 10 numbers into an array and print them in reverse order. */
import java.util.*;
public class Program2
{
public static void main()
{
 Scanner key=new Scanner(System.in);
int[] arr = new int[10];
System.out.println("Enter 10 integers: ");
for(int i=0; i<10; i++)
{
arr[i] = key.nextInt();
}
System.out.println("The integers in reverse are: ");
for(int j=10-1; j>=0; j--)
{
System.out.print(arr[j] + ", ");
}
}
}

Variable Listing:

Variable Datatype Description

arr int[] to store 10 integer elements

i int to cycle through every index of the array (for input)

j int to cycle through every index of the array (for output)

Program 3:
/* Write a Java Program to input 10 numbers into an array and print the values of those cells whose
subscripts are odd. */
import java.util.*;
public class Program3
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] arr = new int[10];
System.out.println("Enter 10 integers: ");
for(int i=0; i<10; i++)
{
arr[i] = key.nextInt();
 }
System.out.println("The cells with odd subscripts are: ");
for(int j=0; j<10; j++)
{
if(j%2!=0)
{
System.out.print(arr[j] + ", ");
}
}
}
}

Variable Listing:

Variable Datatype Description

arr int[] to store 10 integer elements

i int to cycle through every index of the array (for input)

j int to cycle through every index of the array (for output)

Program 4:
/* Write a Java Program to initialize an array of 5 elements and print their sum and average. */
public class Program4
{
public static void main()
{
int[] arr = new int[] {1, 2, 3, 4, 5};
double sum=0;
double average=0;
for(int i=0; i<arr.length; i++)
{
sum+=arr[i];
}
average=sum/arr.length;
System.out.println("The sum of the elements is " + sum + " and the average is " + average);
}
}
Variable Listing:

Variable Datatype Description

arr int[] to store 10 integer elements

sum double to store the sum of the array’s elements

avg double to store the average of the array’s elements

i int to store the index of every element in the array

Program 5:
/* Write a Java Program to input 20 numbers into an array and print the even elements. */
import java.util.*;
public class Program5
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter 20 integers:");
int[] arr=new int[20];
for(int i=0; i<20; i++)
{
arr[i] = key.nextInt();h
}
System.out.println("The even elements are:");
for(int j=0; j<20; j++)
{
if(arr[j]%2==0)
{
System.out.print(arr[j] + ", ");
}
}
}
}

Variable Listing:
 Variable Datatype Description

arr int[] to store 10 integer elements

i int to cycle through every index of the array (for input)

j int to cycle through every index of the array (for output)

Program 6:
/* Write a Java Program to accept values into 2 arrays of 10 cells each. Store the sum of the corresponding
cells in a third array. Display the resultant array. */
import java.util.*;
public class Program6
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] arr1=new int[10];
int[] arr2=new int[10];
System.out.println("Enter 10 integers into array 1:");
for(int i=0; i<10; i++)
{
arr1[i]=key.nextInt();
}
System.out.println("Enter 10 integers into array 2:");
for(int j=0; j<10; j++)
{
arr2[j]=key.nextInt();
}
int[] sum=new int[10];
for(int k=0; k<10; k++)
{
sum[k] = arr1[k] + arr2[k];
}
System.out.println("The resultant array is:");
for(int l=0; l<10; l++)
{
System.out.print(sum[l] + ", ");
}
 }
}

Variable Listing:

Variable Datatype Description

arr1 int[] to store 10 integer elements

arr2 int[] to store 10 integer elements

i int to cycle through every index of the first array (for input)

j int to cycle through every index of the second array (for input)

sum int[] to store the sums of the corresponding integer elements in the
first and second arrays

k int to store the index of every element in the first, second and
resultant arrays

l int to cycle through every index of the resultant array (for output)

Program 7:
/*Two single dimensional arrays contain elements as follows:
X[10] = 5, -3, -2, 1, 0, 12, 14, 16, 25, 13
Y[8] = 6, 5, 10, 15, 18, 20, 22, 30
Write a Java program that results in the third array Z[] as follows:
Z[18] = 5, 6, -3, 5, -2, 10, 1, 15, 0, 18, 12, 20, 14, 22, 16, 30, 25, 13
*/
public class Program7
{
public static void main()
{
int[] X=new int[] {5, -3, -2, 1, 0, 12, 14, 16, 25, 13};
int[] Y=new int[] {6, 5, 10, 15, 18, 20, 22, 30};
int[] Z=new int[X.length + Y.length];
int count_x=0;
int count_y=0;
int count_z=0;
for(int i=0; i<2*Math.min(X.length, Y.length); i++)
 {
if(i%2==0)
{
Z[count_z++] = X[count_x++];
}
else if(i%2==1)
{
Z[count_z++] = Y[count_y++];
}
}
if(X.length>Y.length)
{
for(int j=Y.length; j<X.length; j++)
{
Z[count_z++]=X[j];
}
}
else if(Y.length>X.length)
{
for(int k=X.length; k<Y.length; k++)
{
Z[count_z++]=Y[k];
}
}

for(int l=0; l<Z.length; l++)

{
System.out.print(Z[l] + ", ");
}
}
}

Variable Listing:

Variable Datatype Description

X int[] to store 10 integer elements

Y int[] to store 8 integer elements

 Z int[] to store the elements of X[] and Y[] with alternating subscripts

count_x int to store the index of every element in X[]

count_y int to store the index of every element in Y[]

count_z int to store the index of every element in Z[]

i int to cycle through the index of every element in Z[] from 0 to

2*Math.min(X.length, Y.length)

j int to cycle through the index of every element in Z[] from

Y.length to X.length if X>Y

k int to cycle through the index of every element in Z[] from

X.length to Y.length if Y>X

l int to cycle through the index of every element in Z[] (for output)

Program 8:
/*Write a Java Program to enter marks and names of 10 students and print it in a formatted tabular
manner. */
import java.util.*;
public class Program8
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] names=new String[10];
int[] marks=new int[10];
for(int i=0; i<names.length; i++)
{
System.out.println("Enter name:");
names[i]=key.next();
System.out.println("Enter marks (/500):");
marks[i]=key.nextInt();
key.nextLine();
}
System.out.println("Name:\t\tMarks:");
for(int j=0; j<names.length; j++)
{
System.out.println(names[j] + "\t\t" + marks[j]);
 }
}
}

Program 9:
/*Write a Java Program to store a list of roll numbers and total marks (/500) of 35 students of a class. Print
the maximum of the total marks along with the roll number of the student who attained it.
*/
import java.util.*;
public class Program9
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] roll_nos=new int[10];
int[] marks=new int[10];
for(int i=0; i<roll_nos.length; i++)
{
System.out.println("Enter roll number:");
roll_nos[i]=key.nextInt();
System.out.println("Enter marks (/500):");
marks[i]=key.nextInt();
}
int max_marks=0;
int index=0;
for(int j=0; j<marks.length; j++)
{
if(max_marks<marks[j])
{
max_marks=Math.max(max_marks, marks[j]);
index=j;
}
}
System.out.println("The highest mark was " + max_marks + " attained by roll number " +
roll_nos[index]);
}
}

Program 10:
/* Write a Java Program to initialize an array with the following values:
a[] = {6, 2, 3, 4, 1, 7, 8, 5}
Accept a value from the user and using linear search print the cell position it occupies in the array.
*/
import java.util.*;
public class Program10
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter an integer:");
int search=key.nextInt();
int[] a=new int[] {6, 2, 3, 4, 1, 7, 8, 5};
for(int i=0; i<a.length; i++)
{
if(search==a[i])
{
System.out.println(search + " occupies the cell position " + (i+1));
break;
}
}
}
}

Program 11:
/*Write a Java Program to enter the names of 10 students in an array and ask the user to enter a name.
Locate that particular student using linear search. */
import java.util.*;
public class Program11
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] names=new String[10];
System.out.println("Enter 10 names:");
for(int i=0; i<names.length; i++)
{
names[i]=key.nextLine();
}
 System.out.println("Enter the name to be searched:");
String search=key.nextLine();
int index=0;
boolean found=false;
for(int j=0; j<names.length; j++)
{
if(names[j].compareTo(search)==0)
{
found=true;
index=j;
break;
}
}
System.out.println(search + (found?" occupies the cell position " + (index + 1): " is not in the array"));
}
}

Program 12:
/* Write a Java Program to initialize an array of 10 numeric elements in ascending order. Accept a value
from the user and using binary search, print the cell position that the number occupies in the array. */
import java.util.*;
public class Program12
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] arr=new int[] {2, 3, 7, 9, 12, 15, 18, 19, 22, 27};
System.out.println("Enter an integer to be searched for:");
int search=key.nextInt();
int LL=0;
int UL=arr.length-1;
int m=0;
boolean found=false;
while(LL<=UL)
{
m=(LL+UL)/2;
if(search>arr[m])
{
LL=m+1;
 }
else if(search<arr[m])
{
UL=m-1;
}
else if(search==arr[m])
{
found=true;
break;
}
}
System.out.println(search + (found?" occupies the cell position " + (m+1):" is not in the array"));
}
}

Program 13:
/*Write a Java Program to initialize a sorted array of 10 strings. Accept a value from the user, and using
binary search method, print the position the string occupies in the array. */
import java.util.*;
public class Program13
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] arr=new String[] {"ABC", "BCD", "CDE", "DEF", "EFG", "FGH", "GHI", "HIJ", "IJK",
"JKL"};
System.out.println("Enter a string to be searched for:");
String search=key.nextLine();
int LL=0;
int UL=arr.length-1;
int m=0;
boolean found=false;
while(LL<=UL)
{
m=(UL+LL)/2;
if(search.compareTo(arr[m])>0)
{
LL=m+1;
}
 else if(search.compareTo(arr[m])<0)
{
UL=m-1;
}
else if(search.compareTo(arr[m])==0)
{
found=true;
break;
}
}
System.out.println(search + (found?" occupies the cell position " + (m+1):" is not in the array"));
}
}

Program 14:
/* Write a Java Program to initialize an array of 5 numeric elements and print the array in ascending order
using selection sort. */
public class Program14
{
public static void main()
{
int[] arr=new int[] {18, 22, 7, 12, 9};
int min=0;
int pos=0;
int temp=0;
for(int i=0; i<arr.length; i++)
{
min=arr[i];
pos=i;
for(int j=i+1; j<arr.length; j++)
{
if(arr[j]<min)
{
min=arr[j];
pos=j;
}
}
temp=arr[pos];
arr[pos]=arr[i];
 arr[i]=temp;
}
System.out.println("The array in ascending order is:");
for(int k=0; k<arr.length; k++)
{
System.out.print(arr[k] + ", ");
}
}
}

Program 15:
/* Write a Java Program to initialize an alphanumeric array of 10 elements and print the array in
descending order using selection sort. */
public class Program15
{
public static void main()
{
String[] arr=new String[] {"B2", "D4", "A1", "J10", "E5", "I9", "H8", "G7", "C3", "F6"};
String max="";
int pos=0;
String temp="";
for(int i=0; i<arr.length; i++)
{
max=arr[i];
pos=i;
for(int j=i+1; j<arr.length; j++)
{
if(max.compareTo(arr[j])<0)
{
max=arr[j];
pos=j;
}
}
temp=arr[pos];
arr[pos]=arr[i];
arr[i]=temp;
}
System.out.println("The array in descending order is:");
for(int k=0; k<arr.length; k++)
 {
System.out.print(arr[k] + ", ");
}
}
}

Program 16:
/* Write a Java Program to input 5 vowels into an array and print it out in ascending order using bubble
sort. */
import java.util.*;
public class Program16
{
public static void main()
{
Scanner key=new Scanner(System.in);
char[] arr=new char[5];
System.out.println("Enter 5 vowels:");
for(int k=0; k<arr.length; k++)
{
arr[k]=key.next().charAt(0);
}
char temp=' ';
for(int i=0; i<arr.length; i++)
{
for(int j=0; j<arr.length-1-i; j++)
{
if(arr[j]>arr[j+1])
{
temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
System.out.println("The array in ascending order is:");
for(int l=0; l<arr.length; l++)
{
System.out.print(arr[l] + ", ");
}
 }
}

Program 17:
/* Write a Java Program to initialize 10 names into an array and print them out in alphabetical order
using bubble sort. */
public class Program17
{
public static void main()
{
String[] names=new String[] {"MNO", "ABC", "YZA", "STU", "JKL", "GHI", "VWX", "Vishnu",
"DEF", "PQR"};
String temp=" ";
for(int i=0; i<names.length; i++)
{
for(int j=0; j<names.length-1-i; j++)
{
if(names[j].compareToIgnoreCase(names[j+1])>0)
{
temp=names[j];
names[j]=names[j+1];
names[j+1]=temp;
}
}
}
System.out.println("The names in alphabetical order are:");
for(int k=0; k<names.length; k++)
{
System.out.print(names[k] + ", ");
}
}
}

Program 18:
/* Write a Java Program to input the marks of 7 students into an array, sort the array in descending order
using bubble sort and print it. */
import java.util.*;
public class Program18
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[] marks=new int[7];
System.out.println("Enter the marks of 7 students: (/500)");
for(int k=0; k<marks.length; k++)
{
marks[k]=key.nextInt();
}
int temp=0;
for(int i=0; i<marks.length; i++)
{
for(int j=0; j<marks.length-1-i; j++)
{
if(marks[j] < marks[j+1])
{
temp = marks[j];
marks[j] = marks[j+1];
marks[j+1] = temp;
}
}
}
System.out.println("The marks in descending order are:");
for(int l=0; l<marks.length; l++)
{
System.out.print(marks[l] + ", ");
}
}
}

Program 19:
/* Write a Java Program to enter 10 characters into a character array and print the array in ascending
order using bubble sort. */
import java.util.*;
public class Program19
{
public static void main()
{
 Scanner key=new Scanner(System.in);
char[] arr=new char[10];
System.out.println("Enter 10 characters:");
for(int k=0; k<arr.length; k++)
{
arr[k]=key.next().charAt(0);
}
char temp=' ';
for(int i=0; i<arr.length; i++)
{
for(int j=0; j<arr.length - 1 - i; j++)
{
if(arr[j]>arr[j+1])
{
temp=arr[j];
arr[j]=arr[j+1];
arr[j+1]=temp;
}
}
}
System.out.println("The array in ascending order is:");
for(int l=0; l<arr.length; l++)
{
System.out.print(arr[l] + ", ");
}
}
}

Program 20:
/* Write a Java Program to enter the names of 10 countries along with their corresponding capitals in 2
single dimensional arrays. Accept the value of a country from the user and print its corresponding capital.
*/
import java.util.*;
public class Program20
{
public static void main()
{
Scanner key=new Scanner (System.in);
String[] countries=new String[10];
 String[] capitals=new String[10];
for(int i=0; i<countries.length; i++)
{
System.out.println("Enter the name of a country:");
countries[i]=key.nextLine();
System.out.println("Enter its corresponding capital:");
capitals[i]=key.nextLine();
}
System.out.println("Enter a country to output its capital:");
String search =key.nextLine();
boolean found=false;
int index=0;
for(int j=0; j<countries.length; j++)
{
if(countries[j].compareTo(search)==0)
{
found=true;
index=j;
break;
}
}
System.out.println(found?search + "'s capital is: " + capitals[index]:search + " is not in the array");
}
}

Program 21:
/* Write a Java Program to initialize 9 numbers into a 2-Dimensional array and print it out in a matrix
format using tabs. */
public class Program21
{
public static void main()
{
int[][] arr=new int[][] {{2,4,7}, {1,9,8}, {5,3,6}};
System.out.println("The array in matrix format is:");
for(int i=0; i<arr.length; i++)
{
for(int j=0; j<arr[i].length; j++)
{
System.out.print(arr[i][j] + "\t");
 }
System.out.println();
}
}
}

Program 22:
/* Write a Java Program to initialize 9 characters into a 2-Dimensional array and print the array in
reverse order in a matrix format. */
public class Program22
{
public static void main()
{
char[][] arr=new char[][] {{'a', 'j', 'x'}, {'f', 'u', 'v'}, {'s', 'i', 'h'}};
System.out.println("The array in reverse order is:");
for(int i=arr.length-1; i>=0; i--)
{
for(int j=arr[i].length-1; j>=0; j--)
{
System.out.print(arr[i][j] + "\t");
}
System.out.println();
}
}
}

Program 23:
/* Write a Java Program to enter 9 numbers into a 2-Dimensional array and print a matrix displaying only
the even numbers of the array. */
import java.util.*;
public class Program23
{
public static void main()
{
Scanner key=new Scanner(System.in);
int[][] arr=new int[3][3];
for(int i=0; i<arr.length; i++)
{
 for(int j=0; j<arr[i].length; j++)
{
System.out.println("Enter the element at: " + "(" + i + "," + j + ")" );
arr[i][j]=key.nextInt();
}
}
System.out.println("The matrix with only the even numbers is:");
for(int k=0; k<arr.length; k++)
{
for(int l=0; l<arr.length; l++)
{
if(arr[k][l]%2==0)
{
System.out.print(arr[k][l] + "\t");
}
else
{
System.out.print("*\t");
}
}
System.out.println();
}
}
}

Program 24:
/* Write a Java Program to enter numbers in a 2-Dimensional array with n rows and m columns and print
it in a matrix format. */
import java.util.*;
public class Program24
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
int[][] arr=new int[n][m];
 for(int i=0; i<n; i++)
{
for(int j=0; j<m; j++)
{
System.out.println("Enter the element at: " + "(" + i + "," + j + ")");
arr[i][j]=key.nextInt();
}
}
System.out.println("The matrix is:");
for(int k=0; k<n; k++)
{
for(int l=0; l<m; l++)
{
System.out.print(arr[k][l] + "\t");
}
System.out.println();
}
}
}

Program 25:
/* Write a Java Program to enter numbers into a 2-Dimensional array with n rows and m columns and
print the sum of the elements in each row. */
import java.util.*;
public class Program25
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
int[][] arr=new int[n][m];
for(int i=0; i<n; i++)
{
for(int j=0; j<m; j++)
{
System.out.println("Enter the element at: " + "(" + i + "," + j + ")");
 arr[i][j]=key.nextInt();
}
}
int sum=0;
for(int k=0; k<n; k++)
{
sum=0;
for(int l=0; l<m; l++)
{
sum+=arr[k][l];
}
System.out.println("The sum of the elements in row " + (k+1) + " is: " + sum);
}
}
}

Program 26:
/* Write a Java Program to enter numbers into a 2-Dimensional array with n rows and m columns, store
the sum of the elements in each column in an array and print it. */
import java.util.*;
public class Program26
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
int[][] arr=new int[n][m];
for(int i=0; i<n; i++)
{
for(int j=0; j<m; j++)
{
System.out.println("Enter the element at:" + "(" + i + "," + j + ")");
arr[i][j]=key.nextInt();
}
}
int sum=0;
 int[] columns=new int[m];
for(int k=0; k<m; k++)
{
sum=0;
for(int l=0; l<n; l++)
{
sum+=arr[l][k];
}
columns[k]=sum;
}
System.out.println("The sum of the columns in the array are:");
for(int o=0; o<columns.length; o++)
{
System.out.print(columns[o] + ", ");
}
}
}

Program 27:
/* Write a Java Program to enter numbers into a 2-Dimensional array with n rows and m columns and
print the sum of the left and right diagonal elements. */
import java.util.*;
public class Program27
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
int[][] arr=new int[n][m];
if(m!=n)
{
System.out.println("Error - The matrix should be a square");
​ System.exit(0);
}
for(int i=0; i<n; i++)
{
 for(int j=0; j<m; j++)
{
System.out.println("Enter the element at: " + "(" + i + "," + j + ")");
arr[i][j]=key.nextInt();
}
}
int l_sum=0;
int r_sum=0;
for(int k=0; k<n; k++)
{
for(int l=0; l<m; l++)
{
if(l==k)
{
l_sum+=arr[k][l];
}
if(l+k==m-1)
{
r_sum+=arr[k][l];
}
}
}
System.out.println("The sum of the elements in the left diagonal is: " + l_sum);
System.out.println("The sum of the elements in the right diagonal is: " + r_sum);
}
}

Program 28:
/* Write a Java Program to enter numbers into a 2-Dimensional array with n rows and m columns and
print the upper-left half of the array.
If a[] is:
2 3 4 5 0
3 1 4 7 1
6 7 8 9 3
5 8 2 1 0
2 4 5 7 1
The output will be:
2 3 4 5 0
3 1 4 7
6 7 8
5 8.
2
*/
import java.util.*;
public class Program28
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
int[][] arr=new int[n][m];
if(m!=n)
{
System.out.println("Error - The matrix should be a square");
System.exit(0);
}
for(int i=0; i<arr.length; i++)
{
for(int j=0; j<arr[i].length; j++)
{
System.out.println("Enter the element at: " + "(" + i + "," + j + ")");
arr[i][j]=key.nextInt();
}
}
System.out.println("The upper-left half of the array is:");
for(int k=0; k<arr.length; k++)
{
for(int l=0; l<arr[k].length; l++)
{
if(k+l<n)
{
System.out.print(arr[k][l] + "\t");
}
else
{
System.out.print("\t");
 }
}
System.out.println();
}
}
}

Program 29:
/* Write a Java Program to enter 9 names into a 2-Dimensional array with n rows and m columns and
print the left diagonal elements. */
import java.util.*;
public class Program29
{
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the number of rows in the matrix:");
int n=key.nextInt();
System.out.println("Enter the number of columns in the matrix:");
int m=key.nextInt();
String[][] names=new String[n][m];
if(m!=n)
{
System.out.println("Error - The matrix should be a square");
System.exit(0);
}
for(int i=0; i<names.length; i++)
{
for(int j=0; j<names[i].length; j++)
{
System.out.println("Enter the name at: " + "(" + i + "," + j + ")");
names[i][j]=key.next();
}
}
System.out.println("The left diagonal elements are:");
for(int k=0; k<names.length; k++)
{
for(int l=0; l<names[k].length; l++)
{
 if(k==l)
{
System.out.print(names[k][l] + "\t");
}
else
{
System.out.print("\t");
}
}
System.out.println();
}
}
}

Variable Listing:

Variable Datatype Description

n int to store the number of rows in the matrix

m int to store the number of columns in the matrix

names String[][] to store m • n names in a 2-D array

i int to store the index of every 1-D array inside names[] [row index]
(for input)

j int to store the index of every element in every 1-D array inside
names[] [column index] (for input)

k int to store the index of every 1-D array inside names[] [row index]
(for output)

l int to store the index of every element in every 1-D array inside
names[] [column index] (for output)

Program 30:
/* Write a Java Program to enter the names of 5 students into an array and the marks obtained in another
array. Display the highest marks obtained, along with the name of the students. */
import java.util.*;
public class Program30
{
 public static void main()
{
Scanner key=new Scanner(System.in);
String[] names=new String[5];
int[] marks=new int[names.length];
for(int i=0; i<names.length; i++)
{
System.out.println("Enter the name of the student:");
names[i]=key.nextLine();
System.out.println("Enter the student's marks:");
marks[i]=key.nextInt();
}
int max=0;
int pos=0;
for(int j=0; j<names.length; j++)
{
if(max<marks[j])
{
max=marks[j];
pos=j;
}
}
System.out.println("The highest marks was " + max + " attained by " + names[pos]);
}
}

Variable Listing:

Variable Datatype Description

names String[] to store 5 names

marks int[] to store 5 integers

i int to store the index of every element in names[] / marks[] (for output)

max int to store the current maximum mark in marks[]

pos int to store the index of the current maximum mark in marks[]

j int to cycle through the index of every element in marks[]

Program 31:
/* Write a Java Program to enter the names of students into an array and in another array enter the marks
obtained by 10 students in 2 tests (/100) [using 2-Dimensional array]. Calculate the total marks obtained
by each student and print the name of each student along with the total marks obtained.
*/
import java.util.*;
public class Program31
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] names=new String[10];
int[][] marks=new int[10][2];
for(int i=0; i<names.length; i++)
{
System.out.println("Enter the name of the student:");
names[i]=key.nextLine();
for(int j=0; j<marks[i].length; j++)
{
System.out.println("Enter the marks obtained in test " + (j + 1) + ":");
marks[i][j]=key.nextInt();
}
key.nextLine();
}
int sum=0;
System.out.println("Name\t\tTotal Marks");
for(int k=0; k<names.length; k++)
{
System.out.print(names[k] + "\t\t");
for(int l=0; l<marks[k].length; l++)
{
sum+=marks[k][l];
}
System.out.print(sum);
sum=0;
System.out.println();
}
}
}
Variable Listing:

Variable Datatype Description

names String[] to store 10 names

marks int[][] to store 2 marks per student in a 2-D array

i int to store the index of every element in names[] / every 1-D array
in marks[][] (for input)

j int to store the index of every element in every 1-D array in

marks[][] (for input)

sum int to store the sum of every 1-D array in marks[][] [to store the sum
of each student’s marks]

k int to store the index of every element in names[] (for output)

l int to store the index of every element in every 1-D array inside
marks[][]

Program 32:
/* Write a Java Program to enter the names of cities into a city array and the highest and lowest
temperatures recorded in those cities into a 2-Dimensional temperature array. Display the city
corresponding to the highest temperature and lowest temperature. */
import java.util.*;
public class Program32
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] cities=new String[10];
double[][] temperatures=new double[10][2];
for(int i=0; i<cities.length; i++)
{
System.out.println("Enter the name of a city:");
cities[i]=key.nextLine();
for(int j=0; j<temperatures[i].length; j++)
{
if (j == 0) {
 System.out.println("Enter the city's highest temperature in ºC:");
} else {
System.out.println("Enter the city's lowest temperature in ºC:");
}
temperatures[i][j]=key.nextDouble();
}
key.nextLine();
}
double max_temp=-1000.0;
int max_pos=0;
double min_temp=1000.0;
int min_pos=0;
for(int k=0; k<2; k++)
{
for(int l=0; l<cities.length; l++)
{
if(temperatures[l][k]>max_temp)
{
max_temp=temperatures[l][k];
max_pos=l;
}
else if(temperatures[l][k]<min_temp)
{
min_temp=temperatures[l][k];
min_pos=l;
}
}
}
System.out.println("The city with the highest recorded temperature was: " + cities[max_pos] + " with " +
max_temp + "ºC");
System.out.println("The city with the lowest recorded temperature was: " + cities[min_pos] + " with " +
min_temp + "ºC");
}
}
Variable Listing:

Variable Datatype Description

cities String[] to store 10 cities

temperatures double[][] to store 2 temperatures (max and min) per city in a 2-D array

i int to store the index of every element in cities[] / every 1-D array in
temperatures[][] (for input)

j int to store the index of every element in every 1-D array in

temperatures[][] (for input)

max_temp double to store the highest element in temperatures[][0]

max_pos int to store the row index of the highest element in temperatures[][0]

min_temp double to store the smallest element in temperatures[][1]

min_pos int to store the row index of the lowest element in temperatures[][1]

k int to store the index of every element in every 1-D array inside
temperatures[][] [column index]

l int to store the index of every 1-D array inside temperatures[][] [row
index]

Program 33:
/* Write a Java Program to enter marks obtained by 10 students in 3 subjects (/100) [using 2-Dimensional
array] and calculate the grades of each student according to the average marks:
Avg. Marks​ ​ Grade
<=45.0​ ​ D
>45.0 & <=60.0​ C
>60.0 & <=75.0​ B
>75.0​ ​ A
*/
import java.util.*;
public class Program33
{
public static void main()
{
Scanner key=new Scanner(System.in);
String[] names=new String[10];
double[][] marks=new double[10][3];
for(int i=0; i<names.length; i++)
{
System.out.println("Enter the name of student " + i + ":");
names[i]=key.nextLine();
for(int j=0; j<marks[i].length; j++)
{
System.out.println("Enter the marks obtained in subject " + j + ":");
marks[i][j]=key.nextDouble();
}
key.nextLine();
}
double sum=0;
double average=0;
char grade='D';
System.out.println("Names\t\tAverage\t\tGrade");
for(int k=0; k<names.length; k++)
{
sum=0;
for(int l=0; l<marks[k].length; l++)
{
sum+=marks[k][l];
}
average=sum/3;

if (average <= 45.0) {

grade = 'D';
} else if (average <= 60.0) {
grade = 'C';
} else if (average <= 75.0) {
grade = 'B';
} else {
grade = 'A';
}

System.out.print(names[k] + "\t\t" + average + "\t\t" + grade);

System.out.println();
}
 }
}

Variable Listing:

Variable Datatype Description

names String[] to store 10 names

marks float[][] to store 3 marks per student in a 2-D array

i int to store the index of every element in names[] / every 1-D array
in marks[][] (for input)

j int to store the index of every element in every 1-D array in

marks[][] (for input)

sum float to store the sum of every 1-D array in marks[][] [to store the sum
of each student’s marks]

average float to store the average of the sum of each student’s marks

grade char to store each student’s grade (A/B/C/D)

k int to store the index of every 1-D array inside marks[][] [row index]
(for output)

l int to store the index of every element in every 1-D array inside
temperatures[][] [column index] (for output)

Program 34:
/* Write a Java Program to print the table of 3. [without return, without parameters] */
public class Program34
{
public static void table()
{
for(int i=1; i<=10; i++)
{
System.out.println(i + " * 3 " + "= " + (i*3));
}
}
public static void main()
{
 table();
}
}

Variable Listing:

●​ public static void table()

Variable Datatype Description

i int to store numbers from 1-10

Program 35:
/* Write a Java Program using a menu to add, subtract, multiply and divide 2 numbers. [without return,
without parameters] */
import java.util.*;
public class Program35
{
public static void add()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
System.out.println(n1 + " + " + n2 + " = " + (n1+n2));
}
public static void subtract()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
System.out.println(n1 + " - " + n2 + " = " + (n1-n2));
}
public static void multiply()
{
Scanner key=new Scanner(System.in);
 System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
System.out.println(n1 + " * " + n2 + " = " + (n1*n2));
}
public static void divide()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
System.out.println(n1 + " / " + n2 + " = " + (n1/n2));
}
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter + to add 2 numbers, - to subtract 2 numbers, * to multiply 2 numbers and / to
divide 2 numbers:");
char choice=key.next().charAt(0);
switch(choice)
{
case '+':
{
add();
}
break;
case '-':
{
subtract();
}
break;
case '*':
{
multiply();
}
break;
case '/':
{
 divide();
}
break;
default:
{
System.out.println("Error - Invalid Input");
}
}
}
}

Variable Listing:

●​ public static void main()

Variable Datatype Description

choice char to store the user’s choice of operation (+/-/*//)

●​ public static void add()

Variable Datatype Description

n1 double to store the first number to be added

n2 double to store the second number to be added

●​ public static void subtract()

Variable Datatype Description

n1 double to store the first number to be subtracted

n2 double to store the second number to be subtracted

●​ public static void multiply()

Variable Datatype Description

n1 double to store the first number to be multiplied

n2 double to store the second number to be multiplied

●​ public static void divide()

 Variable Datatype Description

n1 double to store the first number to be divided

n2 double to store the second number to be divided

Program 36:
/* Write a Java Program using a menu to add, subtract, multiply and divide 2 numbers. [with return,
without parameters] */
import java.util.*;
public class Program36
{
public static double add()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
return(n1+n2);
}
public static double subtract()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
return(n1-n2);
}
public static double multiply()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
return(n1*n2);
}
 public static double divide()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
return(n1/n2);
}
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter + to add 2 numbers, - to subtract 2 numbers, * to multiply 2 numbers and / to
divide 2 numbers:");
char choice=key.next().charAt(0);
switch(choice)
{
case '+':
{
System.out.println("The sum is " + add());
}
break;
case '-':
{
System.out.println("The difference is " + subtract());
}
break;
case '*':
{
System.out.println("The product is " + multiply());
}
break;
case '/':
{
System.out.println("The quotient is " + divide());
}
break;
default:
{
System.out.println("Error - Invalid Input");
 }
}
}
}

Variable Listing:

●​ public static void main()

Variable Datatype Description

choice char to store the user’s choice of operation (+/-/*//)

●​ public static double add()

Variable Datatype Description

n1 double to store the first number to be added

n2 double to store the second number to be added

●​ public static double subtract()

Variable Datatype Description

n1 double to store the first number to be subtracted

n2 double to store the second number to be subtracted

●​ public static double multiply()

Variable Datatype Description

n1 double to store the first number to be multiplied

n2 double to store the second number to be multiplied

●​ public static double divide()

Variable Datatype Description

n1 double to store the first number to be divided

n2 double to store the second number to be divided

Program 37:
/* Write a Java Program to print the table of the number n. [without return, with parameters] */
import java.util.*;
public class Program37
{
public static void table(int n)
{
System.out.println("The table of " + n + " is:");
for(int i=1; i<=10; i++)
{
System.out.println(n + " * " + i + " = " + (n*i));
}
}
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter a number:");
int n=key.nextInt();
table(n);
}
}

Variable Listing:

●​ public static void main()

Variable Datatype Description

n int to store the value of the number whose table is to be printed

●​ public static void table(int n)

Variable Datatype Description

n int parameter to store the value of the number whose table is to be

printed

i int to store numbers from 1-10

Program 38:
/* Write a Java Program using a menu to add, subtract, multiply and divide 2 numbers. [without return,
with parameters] */
import java.util.*;
public class Program38
{
public static void add(double n1, double n2)
{
System.out.println(n1 + " + " + n2 + " = " + (n1+n2));
}
public static void subtract(double n1, double n2)
{
System.out.println(n1 + " - " + n2 + " = " + (n1-n2));
}
public static void multiply(double n1, double n2)
{
System.out.println(n1 + " * " + n2 + " = " + (n1*n2));
}
public static void divide(double n1, double n2)
{
System.out.println(n1 + " / " + n2 + " = " + (n1+n2));
}
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter + to add 2 numbers, - to subtract 2 numbers, * to multiply 2 numbers and / to
divide 2 numbers:");
char choice=key.next().charAt(0);
System.out.println("Enter the first number:");
double n1=key.nextDouble();
System.out.println("Enter the second number:");
double n2=key.nextDouble();
switch(choice)
{
case '+':
{
add(n1,n2);
}
break;
case '-':
{
 subtract(n1,n2);
}
break;
case '*':
{
multiply(n1,n2);
}
break;
case '/':
{
divide(n1,n2);
}
break;
default:
{
System.out.println("Error - Invalid Input");
}
}
}
}

Variable Listing:

●​ public static void main()

Variable Datatype Description

choice char to store the user’s choice of operation (+/-/*//)

n1 double to store the first operand

n2 double to store the second operand

●​ public static void add(double n1, double n2)

Variable Datatype Description

n1 double parameter to store the first number to be added

n2 double parameter to store the second number to be added

●​ public static void subtract(double n1, double n2)

 Variable Datatype Description

n1 double parameter to store the first number to be subtracted

n2 double parameter to store the second number to be subtracted

●​ public static void multiply(double n1, double n2)

Variable Datatype Description

n1 double parameter to store the first number to be multiplied

n2 double parameter to store the second number to be multiplied

●​ public static void divide(double n1, double n2)

Variable Datatype Description

n1 double parameter to store the first number to be divided

n2 double parameter to store the second number to be divided

Program 39:
/* Write a Java Program to pass 2 integer values to a function such that the first number is lower than the
second. The integer values will be the range, and the function computes the sum of the values in the range.
[with return, with parameters] */
import java.util.*;
public class Program39
{
public static int sumOfRange(int l, int u)
{
int sum=0;
for(int i=l; i<=u; i++)
{
sum+=i;
}
return(sum);
}
public static void main()
{
Scanner key=new Scanner(System.in);
System.out.println("Enter the first number:");
 int n1=key.nextInt();
System.out.println("Enter the second number:");
int n2=key.nextInt();
if(n1>n2)
{
System.out.println("Error - The first number should be less than the second number");
System.exit(0);
}
System.out.println("The sum of the numbers from " + n1 + " to " + n2 + " is: " + sumOfRange(n1,n2));
}
}

Variable Listing:

●​ public static void main()

Variable Datatype Description

n1 int to store the first number entered by the user

n2 int to store the second number entered by the user

●​ public static int sumOfRange(int l, int u)

Variable Datatype Description

l int parameter to store the lower limit of the range of numbers

u int parameter to store the upper limit of the range of numbers

sum int to store the sum of the numbers between l and u

i int to store the numbers between l and u