1.
Simple calculator
#include <stdio.h>
#include<conio.h>
void main()
int a,b;
float result;
char op;
clrscr();
printf("enter the value for a\n");
scanf("%d",&a);
printf("enter the value for b\n");
scanf("%d",&b);
printf("enter the operation to be performed (+,-,*,/,%)\n");
scanf(" %c",&op);
result=0;
switch(op)
case '+': result=a+b;
break;
case '-': result=a-b;
break;
case '*': result=a*b;
break;
case '/':if(b==0)
printf("divide by zero error\n");
getch();
}
else
result=(float)a/(float)b;
break;
case '%': result=a%b;
break;
default:printf("inavlid operator\n");
getch();
printf("the result is %d%c%d=%f\n",a,op,b,result);
getch();
2. Quadratic equation
#include<stdio.h>
#include<math.h>
#include<conio.h>
void main( )
float x1, x2, a, b, c, d;
clrscr();
printf("Enter the coefficients a, b and c\n");
scanf("%f%f%f",&a,&b,&c);
if(a==0)
printf("the roots doesn't exist\n");
getch();
d=(b*b)-(4*a*c);
if(d == 0)
x1= -b/(2*a);
x2= -b/(2*a);
printf("The roots are real and equal\n");
printf("1st root = %f\n",x1);
printf("2nd root = %f\n",x2);
getch();
else if(d > 0)
x1=(-b+sqrt(d))/(2*a);
x2=(-b-sqrt(d))/(2*a);
printf("The roots are real and distinct\n");
printf("1st root = %f\n",x1);
printf("2nd root = %f\n",x2);
getch();
else
x1=-b/(2*a);
x2=sqrt(fabs(d))/(2*a);
printf("The roots are imaginary\n");
printf("1st root = %f + i%f\n",x1,x2);
printf("2nd root = %f - i%f\n",x1,x2);
getch();
3. Electricity program
#include<stdio.h>
#include<conio.h>
void main()
float units,total_amount;
float charge,surcharge=0;
char name[20];
clrscr();
printf("enter the name\n");
scanf("%s",&name);
printf("enter the number of units consumed\n");
scanf("%f",&units);
if(units>300)
charge=200*.080;
charge=charge+(100*0.90);
charge=charge+(units-300)*1;
else if(units>200)
charge=200*0.80;
charge=charge+(units-200)*0.90;
else
charge=units*0.80;
total_amount=charge+100;
if(total_amount>400)
surcharge=total_amount*0.15;
total_amount=total_amount+surcharge;
printf("total user amount is %f\n",total_amount);
getch();
}
4. Binary search
#include<stdio.h>
#include<conio.h>
void main()
int a[100], n, i, mid, low, high, found, key;
clrscr();
printf("\nEnter the number of elements\n");
scanf("%d",&n);
printf("\nEnter the elements in ascending order\n");
for(i=0; i<n; i++)
scanf("%d", &a[i]);
printf("\nEnter the key element\n");
scanf("%d", &key);
found = 0;
low = 0;
high = n-1;
while(low <= high)
mid = (low+high)/2;
if(key == a[mid])
{
found = 1;
break;
else if(key < a[mid])
high = mid-1;
else
low = mid+1;
if(found==1)
printf("\nKey element %d found at position %d\n", key, mid+1);
else
printf("\nKey element not found\n");
getch();
5. Taylor series
#include<stdio.h>
#include<conio.h>
#include<math.h>
float my_sine(float x, int n);
int fact(int n);
void main()
int x, n;
float rad, res;
clrscr();
printf(" ENTER THE DEGREE");
scanf("%d",&x);
printf("ENTER THE NUMBER OF TERMS");
scanf("%d", &n);
rad=x*(3.142/180);
res=my_sine(rad , n);
printf(" my_sin(%d)=%f\n", x , res);
printf(" Library sine(%d)=%f", x ,sin(rad));
getch();
float my_sine(float x, int n)
int i;
float sum=0;
for(i=1; i<=n; i=i+2)
if((i-1)%4==0)
sum=sum+pow(x , i)/fact(i);
else
sum=sum-pow(x , i)/fact(i);
}
return sum;
int fact(int n)
if(n==0)
return 1;
else
return n*fact(n-1);
6. Matrix multiplication
#include<stdio.h>
#include<conio.h>
void main()
int i, j, a[10][10], b[10][10], c[10][10], k, m,n,p,q;
clrscr();
printf("Enter the array size of 1st matrix");
scanf("%d%d", &m,&n);
printf("Enter the array size of 2nd matrix");
scanf("%d%d",&p,&q);
if(n!=p)
printf("Matrix multiplication is not possible");
}
printf("Enter the elements of 1st matrix");
for(i=0; i<m; i++)
for(j=0;j<n;j++)
scanf("%d", &a[i][j]);
printf("Enter the elements of 2nd matrix");
for(i=0; i<p; i++)
for(j=0; j<q; j++)
scanf("%d", &b[i][j]);
for(i=0; i<m; i++)
for(j=0; j<q; j++)
c[i][j]=0;
for(k=0; k<n; k++)
c[i][j]=c[i][j]+(a[i][k]*b[k][j]);
printf("The resultant matrix is\n");
for(i=0; i<m; i++)
for(j=0; j<q; j++)
printf("%d\t", c[i][j]);
printf("\n");
getch();
7. Bubble sort
#include<stdio.h>
#include<conio.h>
void main()
int a[10], n, i, j, temp;
clrscr();
printf("Enter the number of elements\n");
scanf("%d",&n);
printf("Enter the array elements\n");
for(i=0; i<n; i++)
{
scanf("%d", &a[i]);
for(j=1; j<n; j++)
for(i=0; i<n-j; i++)
if(a[i]> a[i+1])
temp=a[i];
a[i]=a[i+1];
a[i+1]=temp;
printf("The sorted array is\t");
for(i=0; i<n; i++)
printf("%d\t", a[i]);
getch();
}
8. Binary to decimal conversion
#include<stdio.h>
#include<conio.h>
int convert(int bin);
void main()
int bin, dec;
clrscr();
printf("\nEnter the binary value : ");
scanf("%d", &bin);
dec = convert(bin);
printf("\nDecimal equivalent of %d is %d\n", bin, dec);
getch();
int convert(int bin)
if(bin == 0 )
return bin;
else
return (bin%10+2*convert(bin/10));
}
9. String program
#include<stdio.h>
#include<string.h>
#include<conio.h>
void str_cmp(char str1[], char str2[])
if(strcmp(str1,str2)==0)
printf("strings are equal\n");
else
printf("strings are not equal\n");
return ;
void str_len(char str1[])
int n;
n=strlen(str1);
printf("the length of the string is %d\n",n);
return ;
void str_can(char str1[], char str2[])
strcat(str1,str2);
printf("the concatenated string is %s\n",str1);
return;
void main()
char str1[30], str2[30];
clrscr();
printf("enter String 1 :\n ");
scanf("%s", str1);
printf("enter String 2 : \n");
scanf("%s", str2);
str_cmp(str1,str2);
str_len(str1);
str_can(str1,str2);
getch();
10. Structure program
#include<stdio.h>
#include<conio.h>
struct student
int marks;
};
void main()
struct student s[10];
int i, n, sum=0;
float average;
clrscr();
printf("Enter the number of students : \n");
scanf("%d", &n);
printf("Enter the marks of Student \n");
for(i=0; i<n; i++)
scanf("%d ", &s[i].marks);
printf("the marks of Student are\n");
for(i=0; i<n; i++)
printf("%d\n ", s[i].marks);
for(i=0;i<n;i++)
sum=sum+s[i].marks;
average = (float)sum / n;
for(i=0; i<n; i++)
if(s[i].marks > average)
printf("The student %d has scored above average\n",i++);
else
printf("The student %d has scored below average\n", i++);
