title: Variable declaration vs definition
body: <p>I was reading some info on externs.
  Now the author started mentioning variable declaration and definition.
  By declaration he referred to case when: if a variable is declared
  the space for it is not allocated.
  Now this brought me to confusion, because I think <strong>MOST</strong> of the times
  when I use variables in C, I am actually both defining and declaring them right?
  i.e.,</p>
  
  <pre><code>int x; // definition + declaration(at least the space gets allocated for it)
  </code></pre>
  
  <p>I think then that <strong>only</strong> cases in C when you declare the variable but not
  define it is when you use:</p>
  
  <pre><code>extern int x; // only declaration, no space allocated
  </code></pre>
  
  <p>did I get it right?</p>