very simple preprocessor

**brillpsycho** · 11-27-2012

Can anyone tell me why i cant print out the max number? What am i missing? And yes, it has to be defined outside of main. thanks.

Code:

#include <stdio.h>


#define MAX(x,y) ((x)>(y)?(x):(y))

int main(void)
{
    int x=5,y=3;
    printf("max=", MAX(x,y));


    return 0;
}

**Matticus** · 11-27-2012

Code:

main.c||In function 'main':|
main.c|9|warning: too many arguments for format|
||=== Build finished: 0 errors, 1 warnings ===|

Something is missing in here:

Code:

printf("max=", MAX(x,y));

**Salem** · 11-27-2012

Code:

$ gcc -Wall bar.c
bar.c: In function ‘main’:
bar.c:9:5: warning: too many arguments for format [-Wformat-extra-args]

You're missing a %d format.

**std10093** · 11-27-2012

Just for the future be very cautious when you use something like this

Code:

#include <stdio.h>


#define MAX(x,y) ((x)>(y)?(x):(y))

int main(void)
{
    int x=5,y=3;
    printf("max=%d\n", MAX(x++,y));


    return 0;
}

It will give me output 6

Code:

#include <stdio.h>


#define MAX(x,y) ((x)>(y)?(x):(y))

int main(void)
{
    int x=5,y=3;
    printf("max=%d\n", MAX(++x,y));


    return 0;
}

It will give me output 7

This happens because what is in the place of x ( in line where you have the #define ) will be executed too. Same for y.

Thread: very simple preprocessor