77. Validate Configuration Register Layout

#include <stdio.h>
#include <stdint.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // Write logic using pointer access
    uint8_t en = (*cfg).reg & 1;
    uint8_t mode = (*cfg).reg>>1 & 1;
    uint8_t pr = (*cfg).reg>>2 & 3;
    uint8_t res = (*cfg).reg>>4;
    if (en != 1){
        return 0;
    }
    if (pr == 3){
        return 0;
    }
    if (res){
        return 0;
    }
    return 1;
}

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

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

    return 0;
}