title: identifier expected, too few arguments to function (C)
body: <p>My code:
  I have tried multiple ways to fix this but to no avail.
  I have to use <code>scanf</code> in the code so I cannot replace it with <code>fgets</code> as many people have told me to.
  Can someone tell me what's wrong with my code?</p>
  <pre><code>#include &lt;stdio.h&gt;
  
  float Parallel(float R1, float R2);
  
  void main(void) {
      char circ;
      float R1, R2, R3;
      
      printf(&quot;Select Circuit [A/B/X]: &quot;);
      scanf(&quot;%c&quot;, &amp;circ);
      
      if (circ == 'A') {
          printf(&quot;Enter R1 and R2: &quot;);
          scanf(&quot;%f%f&quot;, &amp;R1, &amp;R2);
          printf(&quot;%f%f&quot;, R1, R2);
          Parallel(float R1, float R2);
          printf(&quot;Total resistance for Circuit A is %.2f Ohm&quot;, RT);
      }
      
      if (circ == 'B') {
          printf(&quot;Enter R1, R2 and R3: &quot;);
          scanf(&quot;%f%f%f&quot;, &amp;R1, &amp;R2, &amp;R3);
          Parallel(float R1, float R2);
          RT = RT + R3;
          printf(&quot;Total resistance for Circuit B is %.2f Ohm&quot;, RT);
      }
  
      if (circ == 'X') {
          printf(&quot;That's All&quot;);
      }
  }
          
  float Parallel(float R1, float R2);
  {
      float RT;
      RT = 1 / (1 / R1 + 1 / R2);
      return RT;
  }
  </code></pre>