C Program to Find the Factorial of a Number using Recursion

This is a C Program to find the factorial of a number using recursion.

This C Program Finds the Factorial of a Number using Recursion.

This C Program prints the factorial of a given number using recursion. A factorial is product of all the number from 1 to the user specified number.

Here is the source code of the C program to print the factorial of a given number. The C program is successfully compiled and run on
a Linux system. The program output is also shown below.

/*
 * C Program to find factorial of a given number using recursion
 */
#include <stdio.h>
 
int factorial(int);
 
int main()
{
    int num;
    int result;
 
    printf("Enter a number to find it's Factorial: ");
    scanf("%d", &num);
    if (num < 0)
    {
        printf("Factorial of negative number not possible\n");
    }
    else
    {
        result = factorial(num);
        printf("The Factorial of %d is %d.\n", num, result);
    }
    return 0;
}
int factorial(int num)
{
    if (num == 0 || num == 1)
    {
        return 1;
    }
    else
    {
        return(num * factorial(num - 1));
    }
}

In this C Program, we are reading a number using ‘num’ variable. If else condition statement is used to check the value of ‘num’ variable is less than 0. If the condition is true, then execute the statement and print the factorial of negative number not possible.

Otherwise, if the condition is false, then execute the else statement, the factorial() function is used to find the factorial of a given number using recursion. A factorial is a product of all the number from 1 to the user specified number.

If else condition statement is used to check the ‘num’ variable value is equal to 0 or 1 using logical OR operator. If the condition is true then execute the statement and return value as 1.

Otherwise, if the condition is false, then execute the else statement. Multiply the value of ‘num’ variable with the value of ‘factorial() value and return the value. Print the factorial of a given number using printf statement.

 
$ cc pgm5.c
$ a.out
Enter a number to find it's Factorial: 6
The Factorial of 6 is 720.

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