Check whether two integers have opposite signs in C Solution, output & explanation

#include <stdbool.h>
#include <stdio.h>

bool opposite_signs(int a, int b) {
    return (a ^ b) < 0;          /* sign bit of the XOR is 1 only if the sign bits differ */
}

int main(void) {
    int pairs[][2] = {{5, -3}, {-4, -9}, {7, 0}};
    for (int i = 0; i < 3; i++)
        printf("%d, %d: %s\n", pairs[i][0], pairs[i][1],
               opposite_signs(pairs[i][0], pairs[i][1]) ? "opposite" : "same");
    return 0;
}

5, -3: opposite
-4, -9: same
7, 0: same