title: How to make sure input is a double in the C programming language
body: <p>How do I make sure I've got a double and not something else?</p>
  
  <pre><code>int main() {
      int flagOk = 0;
      double number;
      while(!flagOk) {
          printf("Put in a double");
          scanf("%lf", &amp;number);
          if(number == "%lf"); //this want make sure
          flagOk = 1;
      }
  }
  </code></pre>