I have problem with char in my code,please guide me (c++)
<p>I have problem with char in my code, please guide me (c++).</p>

<p>I have this error: <code>Run-Time Check Failure #3 - The variable 'op' is being used without being initialized</code>. What does it mean and how do I fix it?</p>

<p>This is my code:</p>

<pre><code>#include  &lt;stdio.h&gt;
#include  &lt;iostream&gt;
#include  &lt;stdlib.h&gt;
#include  &lt;conio.h&gt;
#include  &lt;math.h&gt;

using namespace std;
enum Operations {SIN1, COS1, TAN1};

void selectenteroperation(char *szInput) {
    char *szLabels[3] = {"sin", "cos", "tan"};
    int i=0;
    while(strcmp(szInput,szLabels[i])==0)
        ++i;
    switch (i)
    {
        case SIN1: { cout&lt;&lt;"SIN";   break; }
        case COS1: { cout&lt;&lt;"COS";   break; }
        case TAN1: { cout&lt;&lt;"TAN";   break; }
        default:   { cout&lt;&lt;"Wrong"; break; }
    }
}

void main() {
    char *op;
    cout&lt;&lt;"op?";
    cin&gt;&gt;op;
    if(strcmp(op,"sin")==0) selectenteroperation("sin");
    if(strcmp(op,"cos")==0) selectenteroperation("cos");
    if(strcmp(op,"tan")==0) selectenteroperation("tan");
}
</code></pre>
