title: Push and Pop function
body: <p>Im trying to replicate the push and pop functions using integers and an int array. However Im having trouble with finding the size of the array in the push function. How would I find the size or 'push' a new value into the array</p>
  
  <pre><code>typedef int data_t;
  int
  main(int argc, char **argv){
  int *S, i;
  
      S = malloc(10*sizeof(int));
      S = NULL;
      push(1,S);
      push(3,S);
  
      for(i = 0; S[i]; i++){
          printf("%d\n",S[i]);
          }
      return 0;
  }
  
  void
  push(data_t n,int *S ){
      int size = 0, i = 0;
  
      if (S == NULL){
          S[0] = n;
      }
      else{
          while(S[i] != NULL){
              size++;
              i++;
          }
          S[size] = n;
      }
  }
  </code></pre>