Validate Configuration Register Layout

Code

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    if ((cfg->reg & 0x0001) == 0x00) return 0;
    if ((cfg->reg & 0x000C) == 0x0C) return 0;
    if ((cfg->reg & 0xFFF0) != 0) return 0;
    
    return 1;
}

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

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

    return 0;
}

Solving Approach