isdigit confusion

Hi,

According to documentation, isdigit returns a non-zero value is the value passed to it is a decimal integer, 0 otherwise. BUt when i tested it in a simple program it does the opposite. Any ideas?

Code:

---

#include <stdio.h>
#include <ctype.h>

int main()
{
  int c = 33;

  if ( isdigit( c ) == 0 )
      printf( "not an integer\n" );

  system("PAUSE");
  return 0;
}

---

The definition of isdigit:

Quote:

---

7.4.1.5 The isdigit function

Synopsis

1 #include <ctype.h>
int isdigit(int c);

Description
2 The isdigit function tests for any decimal-digit character (as defined in 5.2.1).

---

So it is about decimal-digit characters.... and not about decimal values.

isdigit (5) -> FALSE
isdigit ('5') -> TRUE