77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // Write logic using pointer access
    if (! (cfg->reg & (1 << 0))) {
        return 0;
    } else if ((cfg->reg >> 2) > 0x3) {
        return 0;
    } else 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;
}