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) && ((cfg->reg>>2)&0x11!=0x11) && ((cfg->reg>>4)&0xFFF == 0)) return 1;
    if(!(cfg->reg & 1)) return 0;
    if(((cfg->reg >> 2) & 1) && (cfg->reg >> 3) & 1) return 0;
    if((cfg->reg >> 4) & 0xFFFF) return 0;
    return 1;
}

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

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

    return 0;
}