isdigit function help!!

[rambright]

I read that isdigit() fn returns a non-zero number, if its argument is a digit(0 to 9) and it returns zero otherwise.....

but consider the program.....

#include<iostream>
#include<ctype>
int main()
{

         int c=3;
         if(isdigit(c))
         {
                cout<<"good";
         }
         else
         {
                cout<<"bad";
         }
}

The output comes as bad
why? please help.......

[rambright]

sorry . . . i forgot to type "return 0;" there .... now please help.....

[nvoigt]

You need to pass in a character to check if it is a digit (for example '9' is a digit, 'Z' is not).

[Veneficvs]

Yes, isdigit works only for char types. You declared your variable as integer. The ctype.h functions refer to chars only.

[phantomotap]

O_o

The inherited `std::isdigit' works with `int'.

nvoigt has it right. There is a difference between an integer variable with the integer value of `3' and the "ASCII" character value representing`3'.

int three = 3;

int three = '3'; // correct

Soma