in this code, i can't change parameters i & j . I Don't know why , i am a beginner. plz help me to figure this out . :     #include <iostream>
    using namespace std;

    int rev(int& sourcenum)
    {
	int temp = sourcenum;
	int sum = 0;
	while (temp!=0)
	{
		sum*=10;
		sum += temp%10;
		temp/=10;
	}
	  return sum;
     };

     int main() {
     int i,j;

     cin >> i >> j;

     int add = rev(i)+rev(j);
     cout<<i<<" "<<j<<endl;

     cout<<add<<endl;

     cout<<rev(add);

      }
in this code, i can't change parameters i & j . I Don't know why , i am a beginner. plz help me to figure this out . 
