**Question**

**Write a C++ program that calculates the factorial of a number using a function. The Program should use a While Loop. The program prompts the user to enter an integer from the standard input, calculates and displays the factorial of the inputed number. Draw the Flowchart**

**Answer**

The factorial of a number is obtained by continuously multiplying the number with lower integers in steps of 1.

Fatorial of n is given by

Factorial n = n * (n-1) * (n-2) *… * 2 * 1

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

Flowchart is given below

For the decision, the control continues downwards for NO and branches to the right for YES

C++ Program is given below

//Functions computes the factorial of a number

//By Kindson Munonye

//Date: February 2013

//Date Modified: February 2013

//Location: Port Harcourt, Nigeria

#include ;

#include ;

using namespace std;

int factorial(int n)

{

int fact = 1;

while(n<1) {

fact = fact * n;

n--;

}

return fact;

}

int main()

{

int num;

cout<<"Enter an integer: "; cin>>num;

cout<<"\n\n Factorial "<<num<<" = "<<factorial(num)<<endl;

system("pause");

return 0;

}

//By Kindson Munonye

//Date: February 2013

//Date Modified: February 2013

//Location: Port Harcourt, Nigeria

#include ;

#include ;

using namespace std;

int factorial(int n)

{

int fact = 1;

while(n<1) {

fact = fact * n;

n--;

}

return fact;

}

int main()

{

int num;

cout<<"Enter an integer: "; cin>>num;

cout<<"\n\n Factorial "<<num<<" = "<<factorial(num)<<endl;

system("pause");

return 0;

}