Write a program that lets the user enter a nonnegative integer then uses a loop to calculate the factorial of that number. Display the factorial.

Following are the program in c+ + language

#include / / header file

using namespace std; / / namespace

int main () / / main function

{

int num; / / variable declaration

long int f=1; / / variable declaration

do

{

cout<<"Enter the Positive value:";

cin>>num;

} while (num<0); / / i check whether number is non negative or not

while (num>0) / / iterating over the loop

{

f=f*num; / / calculate the factorial

num--; / / decrement the value of num by 1

}

cout<<" factorial is : "<
return 0;

}

Output:

Enter the Positive value:7

factorial is : 5040

Explanation:

Following are the description of the program.

Read the input by user in the "num" variable of "int" type ... The do-while will check the enter number is nonnegative number. While (n>0) loop is calculating the factorial in the "f" variable. Finally display the factorial.