title: How to compile a simple C code with "$gcc test.c -o demo" command?
body: <p>On this <a href="http://www.tutorialspoint.com/computer_programming/computer_programming_syntax.htm" rel="nofollow">beginner tutorial</a> at TutorialsPoint, it says to save the code as test.c and compile it using "$gcc test.c -o demo" command at CMD.</p>
  
  <p>But I don't have $gcc. What is it?</p>