77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    union{
        unsigned short reg;
        struct{
            unsigned short enable:1;
            unsigned short mode:1;
            unsigned short priority:2;
            unsigned short reserved:12;
        };
    };
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // Write logic using pointer access
    if((1 == cfg->enable) &&
        (3 > cfg->priority) &&
        (0 == cfg->reserved))
        return 1;
    return 0;
}

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

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

    return 0;
}