C Language Boolean Using #define
Example
C of all versions, will effectively treat any integer value other than 0 as true for comparison operators and the integer value 0 as false. If you don't have _Bool or bool as of C99 available, you could simulate a Boolean data type in C using #define macros, and you might still find such things in legacy code.
#include <stdio.h>
#define bool int
#define true 1
#define false 0
int main(void) {
bool x = true; /* Equivalent to int x = 1; */
bool y = false; /* Equivalent to int y = 0; */
if (x) /* Functionally equivalent to if (x != 0) or if (x != false) */
{
puts("This will print!");
}
if (!y) /* Functionally equivalent to if (y == 0) or if (y == false) */
{
puts("This will also print!");
}
}
Don't introduce this in new code since the definition of these macros might clash with modern uses of <stdbool.h>.
