title: Infix to Postfix expression not returning
body: <p>This infix to postfix expression converter is not returning any expression, there is no error when running the code but after I input the expression it should return the string <em><strong>postfix</strong></em> but it doesn't.
  Knowing that the functions: ifOprnd(), prcd(), topStack(), push(), is_emptyy() are all working perfectly</p>
  <pre><code>string
  infinxToPostfix (string ex)
  {
    char topsymb;
    string postfix= &quot;&quot;;
    int i;
    char symb = ex[i];
   
    struct stack e;
    initStack (&amp;e);
    
    for(i = 0; i&lt;symb; i++)
    {
    while (symb != '\0')
      {
        if(ifOprnd(symb))
          postfix+= symb;
        else
        {
          while (!is_emptyy(&amp;e) &amp;&amp; prcd(topStack(&amp;e),symb))
          {    
              topsymb=pop(&amp;e);
              postfix+= topsymb;
          }
          push(&amp;e,symb);
        }
      }
    }
    while(!is_emptyy(&amp;e))
    {
      topsymb=pop(&amp;e);
      postfix+= topsymb;
    }
    return postfix;
  }
  </code></pre>