title: Function to check if input string is an integer or floating point number?
body: <p>Is there a function in C to check if the input is an <code>int</code>, <code>long int</code>, or <code>float</code>?  I know C has an <code>isdigit()</code> function, and I can create an <code>isnumeric</code> function as follows:</p>
  
  <pre><code>int isnumeric( char *str )
  {
      while(*str){
          if(!isdigit(*str))
              return 0;   
          str++;
      }
      return 1;
  }
  </code></pre>
  
  <p>But I was wondering how to create a function that would take a floating point number (as a string) and output a TRUE/FALSE value.  </p>