error in C " expected ')' before float "
<p>I started to read about pointers and I tried to write code for a problem in which the user gives me the radius of a circle and I return to him the perimeter and the surface. When I run this code the compiler shows this : </p>

<pre><code>example.c:16:15: error: expected ‘)’ before ‘float’
void circle(r,float *p,float *s)
                  ^
</code></pre>

<p>My code:</p>

<pre><code>#include &lt;stdio.h&gt;

float pi=3.14159;
void circle(float ,float *,float *);

int main()
{
    float radius,perimeter,surface;
    printf("insert the radius of the circle\n");
    scanf("%f",&amp;radius);
    circle(radius,&amp;perimeter,&amp;surface);
    printf("the perimeter is %f and the surface is %f\n", perimeter, surface );
    return 0;
}

void circle(r,float *p,float *s)
{
    *p=2*pi*r;
    *s=pi*r*r;
}
</code></pre>