C program to find factorial using function

C program to find factorial using function

In this tutorial, we will discuss the concept of C program to find factorial using function

Factorial is a product of all positive descending integer begins with a specified number (n) and calculates up to one

 

Example

factorial of 5 is

5!=5*4*3*2*1=120

 

factorial of 4 is

4!=4*3*2*1=24

 

The factorial of a positive number n is given below

factorial of n is

n!=n*(n-1)*....2*1

 

There are many ways to calculate a factorial using C programming language.  Some of them are described as follows.

The user can provide numbers as they wish and get the factorial according to their input

C program to find factorial of a number using method

Program 1

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int factorial(int);
    int num;
    printf("Enter the number to find factorial\n");
    factorial(num);//call the function
    getch();
    return 0;
    }
    int factorial(num){ //create function to find factorial
        int i,fact=1; //declare variables
        scanf("%d",&num);//get input from user
        for(i=1; i<=num; i++)
            {
                fact=fact*i;//calculate factorial }
    }
        printf("Factorial of given number is: %d\n",fact);

        }

 

When the above code is executed, it produces the following results

Enter a number for find factorial
6
Factorial of the 6 is : 720

 

C program to find factorial of a number using the function with return

Program 2

#include <stdio.h>
#include <stdlib.h>
int factorial(int);
int main()
{
    int num,fact=1;
    printf("Enter the number to find factorial\n");
    scanf("%d",&num);//get input from user
    printf("Factorial of %d is: %d\n",num,factorial(num));
           //call the factorial function to display
getch();
    return 0;
}

int factorial(int num){  //create function to find factorial
int i,fact=1;  //declare variables

for(i=1; i<=num; i++)
fact=fact*i;//calculate factorial
return(fact); //return fact to main

}

When the above code is executed, it produces the following results

Enter a number for find factorial
5
Factorial of the 6 is : 120

 

C program to find factorial of a number using Ternary operator

Program 3

#include <stdio.h>
#include <stdlib.h>

int factorial(int n)//user defined method to calculate factorial
 {
    return(n==1 || n==0) ? 1: n*factorial(n-1);//calculate factorial using ternary operator
}
int main()
{
    int num;
    printf("Enter the number to find factorial\n");
    scanf("%d",&num);//get input from user
    printf("factorial of %d is %d\n",num,factorial(num));
//display factorial of given number
    getch();
    return 0;
}

When the above code is executed, it produces the following results

Enter the number to find factorial
7
Factorialof 7 is 5040

 

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