# Factorial Program In C Using While Loop With Example

Factorial Program In C Using While Loop With Example. If you are looking for a factorial program in C with while loop example, this C programming tutorial will help you to learn how to find the factorial of a number. Just go through this C program to calculate factorial of a number, you will be able to write a factorial C program using while loop.

## Factorial Program in C Using While Loop

Learn how to write a  C program for factorial. Writing a factorial program in C to find factorial can be done using various techniques like using for loop, while loop, pointers, recursion function but here in this program, we show how to write a factorial program using while loop in a proper way.

### Factorial Program in C Using While Loop Source Code

Copy the below program to find the factorial of a number using a while loop or write your own logic by using this program as a reference. Paste the factorial program into C compilers and run the program to see the result.
```/* C PROGRAM FOR FACTORIAL USING WHILE LOOP - FACTORIAL.C */

#include<stdio.h>
#include<conio.h>

void main() //main method

{
//variable declaration
long int calcfact =1;
int i=1,n;

clrscr();

printf("Enter a a positive number : "); //asking user to enter a num
scanf("%d",&n); //reading entered number by user

while(i<=n) //while loop logic for factorial

{

calcfact*=i; //calcfact = calcfact*i;

i++;

}

printf("factorial of %d is = %ld  \n", n, calcfact);

getch();

}```

#### FACTORIAL PROGRAM IN C USING While Loop OUTPUT

After you compile and run the above factorial program in c to find the factorial of a number using while loop, your C compiler asks you to enter a number to find factorial. After you enter your number, the program will be executed and give output like below expected output.

Output – 1

Enter a positive number: 6
Factorial of 6 is = 720

##### FACTORIAL Program in C using Recursion with Explanation
• The program execution starts from main() function.
• Define three variable n, i, calcfact.
• Asks the user to enter a positive number to find factorial using printf().
• Gets the value from the user using scanf() function.
• Let’s take a variable ‘i’ with an initial value of 1 to compare with user entered value ‘n’.
• Now while loop will be executed until the statement while(i<=n) is false.
• In each iteration in while loop, ‘i’ value will be increased (i++) and checked with ‘n’ (i<=n).
• The ‘i’ value is multiplied with ‘calcfact’ variable and the new value will be stored in ‘calcfact’ variable. calcfact*=i; or calcfact = calcfact*i;
• When while statement gets false, the compiler gets out of the while loop and prints the factorial of the entered number.
• 1*2*3*4*5*6 = 720

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