cin and buffer problem

Question

Hi I have question regarding cin and buffer. I want to make a simple io program which takes integers.

Anyway I stumbled to a problem with buffer. Using MinGW in windows7 the following code will print out all four integers that I input. But when I switch to SunOS and compile it with G++ it will only print out the first integer. Is this a compiler issue or is it a operating system issue?

#include <iostream>

using namespace std;

int main()
{
   int i;

   cout << "Enter four integers: ";
   cin >> i;
   cout << "\nYou entered the numbers: " << i << " ";

   cin >> i; cout << " ";
   cin >> i; cout << " ";
   cin >> i; cout << " ";

   return 0;
}

Answer 1

The code should print out the first number on pretty any system.

cout << " ";

versus

cout << " " << i;

Therefore many guidelines state to do only one operation per line. The cin just optically clutters the reading. Actually you never output i excepted the first time.

Answer 2

In these lines:

cin >> i; cout << " ";
cin >> i; cout << " ";
cin >> i; cout << " ";

...you're reading a number (if possible) but then just printing out a space, not the number you just read. If you really need to do this, I'd probably write a small function, and use it:

int get_input() { 
    int ret;
    cin >> ret;
    cout << ret;
    return ret;
}

// ...
cout << "Enter four integers: ";

for (int i=0; i<4; i++)
    get_input();

I can't say I'm particularly excited about that function, but under the circumstances, it's probably at least a little better than nothing (just not much better).