error C2065: undeclared identifier
<p>This is a very basic problem, I need to find the area and volume of a sphere but I am getting this error:</p>

<pre><code> error C2065: 'v' : undeclared identifier
 error C2065: 'a' : undeclared identifier
</code></pre>

<p>Here is my program:</p>

<pre><code>#include &lt;iostream&gt;
#include &lt;cmath&gt;
#include &lt;iomanip&gt;

using namespace std;
int r;
int computeSphere(int r) {
    double a,v;
    a = 4*3.14* pow(r,2);
    v = (4/3) * 3.14 * pow(r,3);

    return a,v;
}

int main() {
    cout &lt;&lt; "Enter the radius: ";
    cin &gt;&gt; r;
    cout &lt;&lt; fixed &lt;&lt; setprecision(2);

    computeSphere(r);

    cout &lt;&lt; "The area of a sphere of radius " &lt;&lt; r &lt;&lt; " is " &lt;&lt; a &lt;&lt; " and its ";
    cout &lt;&lt; "volume is ";
    cout &lt;&lt; v;
    cout &lt;&lt; endl;

    return 0;
}
</code></pre>

<p>the question says that The function should not perform any I/O operations. 
so how can I show the results ?? </p>
