77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    if((cfg->reg & 1) != 1) return 0;
    if(((cfg->reg >>2) & (0x3)) > 2) return 0;
    if((cfg->reg >>4 ) > 0) return 0;
    
    return 1;
}

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

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

    return 0;
}