Factorial Output error

Question

#include <iostream>
using namespace std;

int main()
{
int a,num;
num=0;
cout<<"Enter the number you want factorial of \n";
cin>>a;
for(int x=a-1;x>0;x--)
{
num=a*x;
cout<<x<<endl;
}
cout<<"Factorial is "<<num;
return 0;
}

what's wrong here?

Answer 1

Hi! There is really big error.
You will always get Factorial is {value of a(not value of num!!!)}.
What is the cause? In your for-loop you update your num variable on each iteration. So in last iteration it looks like this:
x=1;
a=12;
num = a*x;//you get 12 as a result
What is the solution? You must save num variable.
int main()
{
int a,num;
num=1;//necessary to initialize multiplication with 1
cout<<"Enter the number you want factorial of \n";
cin>>a;
for(int x=a-1;x>0;x--)
{
//we will increase this variable. Not update
num* = x;
cout<<x<<endl;
}
cout<<"Factorial is "<<num;
return 0;
}

Answer 2

Thank You very Much!! I got the issue. And for(int x=a... not x=a-1... )

Thank You very much. :))

Answer 3

You're welcome:)

Answer 4

fact=1
for(i=n;i>=1;i++)
fact=fact×i