C Program to Find Factorial of a Number

To understand this example, you should have the knowledge of the following C programming topics:

The factorial of a positive number n is given by:

factorial of n (n!) = 1 * 2 * 3 * 4....n

The factorial of a negative number doesn't exist. And, the factorial of 0 is 1.

Factorial of a Number

Output

Enter an integer: 10
Factorial of 10 = 3628800

This program takes a positive integer from the user and computes the factorial using for loop.

Since the factorial of a number may be very large, the type of factorial variable is declared as unsigned long long.

If the user enters a negative number, the program displays a custom error message.

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