Level: Easy
1.Write a C program to convert Total days to year, month, and days.
C
#include <stdio.h>
int main() {
int totalDays, years, months, days;
printf("Enter the total number of days: ");
scanf("%d", &totalDays);
years = totalDays / 365;
totalDays %= 365;
months = totalDays / 30; // Assuming an average of 30 days per month
days = totalDays % 30;
printf("Years: %d\n", years);
printf("Months: %d\n", months);
printf("Days: %d\n", days);
return 0;
}
Output:
Enter the total number of days: 400
Years: 1
Months: 1
Days: 5
2.C program to convert temperature from Fahrenheit to Celsius and vice versa
C
#include <stdio.h>
int main() {
float fahrenheit, celsius;
char choice;
printf("Enter 'F' to convert Fahrenheit to Celsius or 'C' to convert Celsius to Fahrenheit: ");
scanf(" %c", &choice); // Note the space before %c to consume any leftover newline character
if (choice == 'F' || choice == 'f') {
printf("Enter temperature in Fahrenheit: ");
scanf("%f", &fahrenheit);
celsius = (fahrenheit - 32) * 5 / 9.0;
printf("Temperature in Celsius: %.2f\n", celsius);
} else if (choice == 'C' || choice == 'c') {
printf("Enter temperature in Celsius: ");
scanf("%f", &celsius);
fahrenheit = (celsius * 9 / 5.0) + 32;
printf("Temperature in Fahrenheit: %.2f\n", fahrenheit);
} else {
printf("Invalid choice.\n");
}
return 0;
}
Output:
Enter 'F' to convert Fahrenheit to Celsius or 'C' to convert Celsius to Fahrenheit: F
Enter temperature in Fahrenheit: 68
Temperature in Celsius: 20.00
3.Write a C Program to Accept ten numbers and display the sum of even and the product
of odd numbers
C
#include <stdio.h>
int main() {
int numbers[10];
int sumEven = 0, productOdd = 1;
int i, countOdd = 0;
printf("Enter 10 numbers:\n");
for (i = 0; i < 10; i++) {
scanf("%d", &numbers[i]);
if (numbers[i] % 2 == 0) {
sumEven += numbers[i];
} else {
productOdd *= numbers[i];
countOdd++;
}
}
printf("Sum of even numbers: %d\n", sumEven);
if (countOdd > 0) {
printf("Product of odd numbers: %d\n", productOdd);
} else {
printf("No odd numbers entered.\n");
}
return 0;
}
Output:
Enter 10 numbers:
1 2 3 4 5 6 7 8 9 10
Sum of even numbers: 30
Product of odd numbers: 945
4.Write a C Program to generate a Multiplication table of a given input number.
C
#include <stdio.h>
int main() {
int number, i;
printf("Enter a number: ");
scanf("%d", &number);
printf("Multiplication table of %d:\n", number);
for (i = 1; i <= 10; i++) {
printf("%d x %d = %d\n", number, i, number * i);
}
return 0;
}
Output:
Enter a number: 5
Multiplication table of 5:
5x1=5
5 x 2 = 10
5 x 3 = 15
5 x 4 = 20
5 x 5 = 25
5 x 6 = 30
5 x 7 = 35
5 x 8 = 40
5 x 9 = 45
5 x 10 = 50
5. Write a C Program to calculate simple interest.
```c
#include <stdio.h>
int main() {
float principal, rate, time, simpleInterest;
printf("Enter principal amount: ");
scanf("%f", &principal);
printf("Enter rate of interest: ");
scanf("%f", &rate);
printf("Enter time (in years): ");
scanf("%f", &time);
simpleInterest = (principal * rate * time) / 100;
printf("Simple Interest: %.2f\n", simpleInterest);
return 0;
}
```
**Output:**
```
Enter principal amount: 1000
Enter rate of interest: 5
Enter time (in years): 2
Simple Interest: 100.00
```
6.Write a C Program to Swap 2 numbers with a third variable
C
#include <stdio.h>
int main() {
int a, b, temp;
printf("Enter two numbers: ");
scanf("%d %d", &a, &b);
printf("Before swapping: a = %d, b = %d\n", a, b);
temp = a;
a = b;
b = temp;
printf("After swapping: a = %d, b = %d\n", a, b);
return 0;
}
Output:
Enter two numbers: 10 20
Before swapping: a = 10, b = 20
After swapping: a = 20, b = 10
7.Write a C Program to find Quotient and Remainder
C
#include <stdio.h>
int main() {
int dividend, divisor, quotient, remainder;
printf("Enter dividend: ");
scanf("%d", ÷nd);
printf("Enter divisor: ");
scanf("%d", &divisor);
if (divisor == 0) {
printf("Error: Divisor cannot be zero.\n");
return 1; // Indicate an error
}
quotient = dividend / divisor;
remainder = dividend % divisor;
printf("Quotient: %d\n", quotient);
printf("Remainder: %d\n", remainder);
return 0;
}
Output:
Enter dividend: 25
Enter divisor: 4
Quotient: 6
Remainder: 1
8.Write a C Program to calculate Area and Circumference of a circle based on user input
C
#include <stdio.h>
#include <math.h> // For M_PI (pi)
#define M_PI 3.14159 // You can also use this to define PI
int main() {
float radius, area, circumference;
printf("Enter the radius of the circle: ");
scanf("%f", &radius);
area = M_PI * radius * radius;
circumference = 2 * M_PI * radius;
printf("Area: %.2f\n", area);
printf("Circumference: %.2f\n", circumference);
return 0;
}
Output:
Enter the radius of the circle: 3.5
Area: 38.48
Circumference: 21.99
9.Write a C Program to find the largest number of the three.
C
#include <stdio.h>
int main() {
int num1, num2, num3, largest;
printf("Enter three numbers: ");
scanf("%d %d %d", &num1, &num2, &num3);
largest = num1; // Assume num1 is the largest initially
if (num2 > largest) {
largest = num2;
}
if (num3 > largest) {
largest = num3;
}
printf("The largest number is: %d\n", largest);
return 0;
}
Output:
Enter three numbers: 15 8 22
The largest number is: 22
10.Write a C Program to calculate the grade of the student according to the specified
marks.
C
#include <stdio.h>
int main() {
int marks;
printf("Enter the student's marks: ");
scanf("%d", &marks);
if (marks >= 90) {
printf("Grade: A+\n");
} else if (marks >= 80) {
printf("Grade: A\n");
} else if (marks >= 70) {
printf("Grade: B\n");
} else if (marks >= 60) {
printf("Grade: C\n");
} else if (marks >= 50) {
printf("Grade: D\n");
} else {
printf("Grade: Fail\n");
}
return 0;
}
Output:
Enter the student's marks: 75
Grade: B
Level: Medium
1.Write a C program to multiply two numbers using the plus operator.
C
#include <stdio.h>
int multiply(int a, int b) {
int result = 0;
for (int i = 0; i < b; i++) {
result += a;
}
return result;
}
int main() {
int num1, num2, product;
printf("Enter two numbers: ");
scanf("%d %d", &num1, &num2);
if (num2 < 0)
{
printf("Error: Second number must be positive.\n");
return 1;
}
product = multiply(num1, num2);
printf("Product: %d\n", product);
return 0;
}
Output:
Enter two numbers: 6 7
Product: 42
2.Write a C Program to check whether the input number is a palindrome or not
C
#include <stdio.h>
int main() {
int number, reversedNumber = 0, remainder, originalNumber;
printf("Enter an integer: ");
scanf("%d", &number);
originalNumber = number;
while (number != 0) {
remainder = number % 10;
reversedNumber = reversedNumber * 10 + remainder;
number /= 10;
}
if (originalNumber == reversedNumber) {
printf("%d is a palindrome.\n", originalNumber);
} else {
printf("%d is not a palindrome.\n", originalNumber);
}
return 0;
}
Output:
Enter an integer: 12321
12321 is a palindrome.
3.Write a C Program to check whether the given number is an Armstrong or not
C
#include <stdio.h>
#include <math.h>
int main() {
int number, originalNumber, remainder, n = 0;
float result = 0.0;
printf("Enter an integer: ");
scanf("%d", &number);
originalNumber = number;
// Count the number of digits
originalNumber = number;
while (originalNumber != 0) {
originalNumber /= 10;
++n;
}
originalNumber = number;
while (originalNumber != 0) {
remainder = originalNumber % 10;
result += pow(remainder, n);
originalNumber /= 10;
}
if ((int)result == number) {
printf("%d is an Armstrong number.\n", number);
} else {
printf("%d is not an Armstrong number.\n", number);
}
return 0;
}
Output:
Enter an integer: 153
153 is an Armstrong number.
4.Write a C Program to check whether the given number is a prime or not
C
#include <stdio.h>
#include <stdbool.h>
int main() {
int number, i;
bool isPrime = true;
printf("Enter a positive integer: ");
scanf("%d", &number);
if (number <= 1) {
isPrime = false;
} else {
for (i = 2; i <= number / 2; i++) {
if (number % i == 0) {
isPrime = false;
break;
}
}
}
if (isPrime) {
printf("%d is a prime number.\n", number);
} else {
printf("%d is not a prime number.\n", number);
}
return 0;
}
Output:
Enter a positive integer: 29
29 is a prime number.
5.Write a C Program to generate Fibonacci series
#include <stdio.h>
int main() {
int n, i, t1 = 0, t2 = 1, nextTerm;
printf("Enter the number of terms: ");
scanf("%d", &n);
printf("Fibonacci Series: ");
for (i = 1; i <= n; i++) {
printf("%d, ", t1);
nextTerm = t1 + t2;
t1 = t2;
t2 = nextTerm;
}
printf("\n");
return 0;
}
```
**Output:**
```
Enter the number of terms: 10
Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34,
```
6.Write a C Program to print the factorial of a number
C
#include <stdio.h>
int main() {
int n, i;
unsigned long long factorial = 1;
printf("Enter an integer: ");
scanf("%d", &n);
if (n < 0) {
printf("Error: Factorial of a negative number doesn't exist.\n");
} else {
for (i = 1; i <= n; i++) {
factorial *= i;
}
printf("Factorial of %d = %llu\n", n, factorial);
}
return 0;
}
Output:
Enter an integer: 6
Factorial of 6 = 720
7.Write a C Program to reverse a given number
C
#include <stdio.h>
int main() {
int number, reversedNumber = 0, remainder;
printf("Enter an integer: ");
scanf("%d", &number);
while (number != 0) {
remainder = number % 10;
reversedNumber = reversedNumber * 10 + remainder;
number /= 10;
printf("Reversed Number: %d\n", reversedNumber);
return 0;
}
Output:
Enter an integer: 12345
Reversed Number: 54321
8.Write a C Program to generate the following pattern:
#include <stdio.h>
int main() {
int rows = 3; // Number of rows in the pattern
int i, j;
for (i = 1; i <= rows; i++) {
printf("$");
for (j = 1; j <= i + 2; j++) {
printf("*");
printf("$\n");
return 0;
Output:
***
****
*****
9.Write a C Program to generate the following pattern:
1
12
123
1234
12345
C
#include <stdio.h>
int main() {
int rows = 5; // Number of rows in the pattern
int i, j;
for (i = 1; i <= rows; i++) {
for (j = 1; j <= i; j++) {
printf("%d", j);
printf("\n");
return 0;
}
Output:
1
12
123
1234
12345
10.Write a C Program to calculate the sum of Natural Numbers.
C
#include <stdio.h>
int main() {
int n, i, sum = 0;
printf("Enter a positive integer: ");
scanf("%d", &n);
if (n < 1) {
printf("Error: Please enter a positive integer.\n");
return 1; // Indicate an error
for (i = 1; i <= n; i++) {
sum += i;
}
printf("Sum of natural numbers up to %d is: %d\n", n, sum);
return 0;
Output:
Enter a positive integer: 10
Sum of natural numbers up to 10 is: 55
