Calculating the recursive factorial of an integer in C

The factorial of a natural number n is the product of integers less than or equal to it.
n! means that we start from n and we decrement until we reach the number 1.

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

Example

Algorithm

Start

fact: integer;

fact ß 1 ;

For i from 1 to N do

fact ß fact

End do

Fin

The program that calculates the factorial of an integer:

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

//iterative 
unsigned long fact (unsigned short value) {
 int res = 1; 
 for(int i = 1; i <= value; i++) {
 res *= i;
 }
 return res; 
}

//recursive
unsigned long fact_recursive (unsigned short number)
{
 if (number == 0)
 return 1; 
 else
 return number * fact_recursive(number - 1); 

}

int main()
{
 int number; 
 printf("Enter a number: "); 
 scanf("%d",& number); 
 printf("factorial of %d: %d\n",number,fact); 
 return 0; 
}

References:
La factorielles - wikipedia

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Jean Dupont Il y a 2 heures

Excellent tutoriel ! J'ai enfin compris comment utiliser Apache POI correctement.

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CodeurJava ✓ Auteur • Il y a 1 heure

Merci Jean ! N'hésitez pas si vous avez des questions.