77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    return ((cfg->reg & 1) &&
            (((cfg->reg & 0x000C) >> 2) ^ 0x11) &&
            !(cfg->reg & 0xFFF0));
}

int main() {
    ConfigRegister cfg;
    scanf("%hx", &cfg.reg);

    int result = validate_config(&cfg);
    printf("%d", result);

    return 0;
}