title: Warning when using printf
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/14069226/c-warning-implicit-declaration-of-function-printf">c - warning: implicit declaration of function ‘printf’</a>  </p>
  </blockquote>
  
  
  
  <p>Just learning C. I'm getting warnings in a hello world program:</p>
  
  <pre><code>main()
  {
      printf("Hi\n");
  }
  </code></pre>
  
  <p>here's the warning:</p>
  
  <pre><code>x.c: In function 'main':
  x.c:2: warning: incompatible implicit declaration of built-in function 'printf'
  </code></pre>
  
  <p>How can I eliminate it?</p>