/*
  The Program for calculating factorial of a no.
  Here, Fact is a recursive function
  It will calculate factorial as below

 if user input is 4
 fact(4)        // call from main m=4,n=4;
 fact(4-1)*4 will call function it self as recursion
      fact(3)   m=3   
      fact(3-1)*3
          fact(2)
          fact(2-1)*2
               fact(1)    // it will return 1 to last cll of fact
          (1 * 2)      // 1 comes from upper call's return value
      ((1*2) *3) = (2*3)  //  2 comes from very upper call's return value
( (1*2*3) * 4) 
(6*4)=24                        // 6 comes from upper last call of fact's return values
and at last 24 will return to main


The program code for showing the recursion mechanism of function.
It will maintain stack call internally for manipulating function calls and
values at diffrent call.
*/
#include "iostream"
#include "conio.h"
using namespace std;

int fact(int m)
{
    if(m==1)
        return 1;
    return fact(m-1)*m;
}

int main(void)
{
    int no=5;
    cout<<"Enter No to calculate factorial of it : ";
    cin>>no;
    cout<<"factorial of "<< no <<" is  "<< fact(no);
    getch();
    return 0;
}