Control Register Using Nested Bitfields

Code

#include <stdio.h>

typedef union {
    unsigned char reg;
    struct {
        unsigned char enable : 1;
        unsigned char mode : 1;
        unsigned char priority : 2;
        unsigned char reserved : 4;
    } bits;
} ControlRegister;

// Write your logic here
int validate_register(ControlRegister *ctrl) {
    int a,b,c;
    a=ctrl->bits.enable;
    b=(ctrl->bits.priority)<=2;
    c=((ctrl->bits.reserved)==0x0);
    return (a)&(b)&(c);
}

int main() {
    ControlRegister ctrl;
    scanf("%hhx", &ctrl.reg);

    int result = validate_register(&ctrl);
    printf("%d", result);

    return 0;
}

Solving Approach

get to know the syntax , pointer->struct.bitfield , also how to declare the specific bit in structure