title: error C2065: undeclared identifier
body: <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>