The program consists of the following steps:
- The user is prompted to enter a number.
- The factorial() function is defined to calculate the factorial recursively. It takes an integer parameter n and returns the factorial of n.
- Inside the factorial() function a base case is defined where the factorial of 0 is 1.
- For any other value of n, the factorial() function recursively calls itself with the n-1 and multiplies the result by n.
- In the main() function, user input is stored in the variable num.
- The factorial() function is called with input number and the result is stored in the variable fact.
- Finally, calculated factorial is printed to the console.
Here's a simple C program to calculate the factorial of a given number:
#include <stdio.h>
// Function to calculate factorial
int factorial(int n) {
if (n == 0) {
return 1;
}
// Recursive case: multiply n by the factorial of (n-1)
else {
return n * factorial(n - 1);
}
}
int main() {
int num;
// Input number from user
printf("Enter a number: ");
scanf("%d", &num);
// Calculate factorial
int fact = factorial(num);
// Print the factorial
printf("Factorial of %d is %d\n", num, fact);
return 0;
}
output :
Enter a number: 5
Factorial of 5 is 120
Explanation:
- The factorial() function calculates the factorial of a given number n recursively.
- It has a base case when n is 0, where the factorial is 1.
- For any other value of n, it recursively calls itself with n-1 and multiplies the result by n.
- In the main() function, the user inputs a number.
- The factorial() function is called with the input number and the result is stored in fact.
- Finally, calculated factorial is printed to console.
