#include<iostream>
using namespace std;
int main()
{
    int a,b;
    cout<<"a" <<endl;
    cin>>a;
    cout<<"b" <<endl;
    cin>>b;
    cout<<a+b <<endl;
    system("pause");
}

Can you tell me what's the prob?????????

Read FAQ
http://acm.timus.ru/help.aspx?topic=faq

I don't understand what is the meaning of output and input even though i read the website you have told me. Can you briefly tell me about the meaning of output and input and the meaning of these two? I hope I can learn something from you.

This problem haven't say print "a"and"b"letter before input.So I change your programme.
 #include<iostream>
using namespace std;
int main()
{
int a,b;

cin>>a;

cin>>b;
cout<<a+b <<endl;
system("pause");//return 0;
}

this can be better:
#include<iostream>
using namespace std;
int main()
{
  int a,b;
  while(cin>>a>>b)
  {cout<<a+b<<endl;}
  return 0;
}

Edited by author 21.11.2009 15:02