title: What's the difference among (const char *str) , (char const *str) and (char *const str)?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/890535/what-is-the-difference-between-char-const-and-const-char">What is the difference between char * const and const char *?</a><br>
    <a href="https://stackoverflow.com/questions/4949254/const-char-const-versus-const-char">const char * const versus const char *?</a>  </p>
  </blockquote>
  
  
  
  <p>as we define a function in c,we may use (const char *str) , (char const *str) or (char *const str) as a variable.What's the difference among them?</p>