double evaluation

#include <stdio.h>
#include <stdlib.h>

#define MINVAL(A,B)( A<B ? A : B )
#define MAXVAL(A,B)( A>B ? A : B )

int main (int argc, char **argv){

int a = 1;
int b = 2;

printf("%d\n",MINVAL(a,b));
printf("%d\n",MAXVAL(a,b));

//int result = a++ < b++ ? a++ : b++;
//int result = a++ > b++ ? a++ : b++;

printf("%d\n",MINVAL(a++,b++));
printf("%d\n",MAXVAL(a++,b++));

return 0;
}

/*
output:

1
2
2
4

*/