title: C error: pointer expected
body: <p>I made a simple program in C that finds if a number is prime. I am new to C and decided to try to use scanf instead of hardcoded numbers to check. When I run my code:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  typedef int bool;
  #define true 1
  #define false 0
  int main(){
    //I am going to check if the "checking" variable is a prime
    int checking;
  
    scanf("%d",checking);
  
    //"stopper" is where the for loop will stop
    int stopper = checking**0.5 + 1;
  
    //"found" will show if I have found something bad
    bool found = false;
  
    for (int i = 2; i &lt; stopper; i++)
    {
      if (checking % i == 0){found = true; break;}
    }
  
    if (!found) {printf("it is prime");}
    else {printf("it is not prime");}
  
  }
  </code></pre>
  
  <p>when I try to compile this with TCC it gives the error (primes.c is the name of the document)</p>
  
  <pre><code>primes.c:12 error: pointer expected
  </code></pre>
  
  <p>I don't know how to fix this.</p>
  
  <p>EDIT: I just made stopper = checking/2 and the program crashes</p>