what is compilation error in c++? : <p>i am attending a online competition. my code is working in my compilier visual studio 2013. but the online judges giving me compilation error.
here is my code.</p>

<pre><code>    #include&lt;iostream&gt;
#include&lt;string&gt;
#include&lt;cmath&gt;
#include&lt;fstream&gt;
using namespace std;

void main() {

    int first_number;
    int  second_number;

    string str;
    char ch;
    int count = 0;

    ifstream yfile("q4.txt");

    while (!yfile.eof())
    { 
        yfile &gt;&gt;first_number;

        if (first_number &lt; 0)
            first_number = abs(first_number);

        yfile &gt;&gt; ch;
        yfile &gt;&gt; second_number;

        if (second_number &lt; 0)
            second_number = abs(second_number);

        int  gcd;
        for (int i = 1; i &lt;= first_number&amp;&amp;i &lt;= second_number; i++){


            if (first_number%i == 0 &amp;&amp; second_number%i == 0){

                gcd = i;

            }

        }

        cout &lt;&lt; "Output:    " &lt;&lt; gcd &lt;&lt; endl;



    }
</code></pre>

<p>can anyone please tell me solution? I will be thankful to you.
}</p>
