Validate Configuration Register Layout

Code

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {

    int flag =1;
    if(cfg->reg & 0x01 == 0) flag = 0;
    if((cfg->reg >> 2 & 0x03) == 3) flag = 0;
    if((cfg->reg  & 0xFFF0) != 0) flag =0;

    return flag;
}
//1111 1111 1111 111 1  0101

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

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

    return 0;
}

Solving Approach