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) {
 if(((ctrl->reg)& 0x01)==1 )
    { 
            if(((ctrl->reg) & 0x02)>>1==0)
             { 
                if(((ctrl->reg) & 0x0C)>>2<=2)
                {
                    if(((ctrl->reg) & 0xF0)>>4==0)
                    {
                        return  1;
                    }
                }
             }
    }
    return 0;
}

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

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

    return 0;
}

Solving Approach