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) {

    ControlRegister res=*ctrl;
    if ((res.bits.enable == 1)&&(res.bits.priority<=2)&&(res.bits.reserved==0))
   { return 1;}
    else {return 0;}
    
}

int main() {
    ControlRegister ctrl;// typedef union and its object to store the value in reg
    scanf("%hhx", &ctrl.reg);

    int result = validate_register(&ctrl);// address of the the union;
    printf("%d", result);

    return 0;
}

Solving Approach