title: Two similar codes, when they are run on two different computers
body: <p>Two similar codes, when they are run on two different computers, give two right answers, but they look different. How could it be explained? The aim is to calculate A+B. </p>
  
  <p>Input: 1000000000 1000000000 </p>
  
  <p>Output-1: 2000000000 </p>
  
  <p>Output-2: 2e+009</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;fstream&gt;
  using namespace std;
  int main(){
    ifstream cin("input.txt");
    ofstream cout("output.txt");
    int a, b;
    cin &gt;&gt; a &gt;&gt; b;
    cout &lt;&lt; a + b;
    return 0;
  }
  </code></pre>