Validate Configuration Register Layout

Code

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // check if enable bit is set
    if(!((cfg->reg)&1))
        return 0;
    
    // check bits 2 and 3 aren't both set
    if( (((cfg->reg)>>2)&0x3) == 3 )
        return 0;

    // check if bit 4 - 15 are 0
    if( ((cfg->reg)>>4))
        return 0;

    return 1;
}

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

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

    return 0;
}

Solving Approach