OOP344 Week 11: Copy Bits

The following is the code for copying bits from a mask to a number:

#include <cstdio>

void prnBits(unsigned int val){
    unsigned int m = 1 << sizeof(val)*8-1;
    while(m){
        printf("%d", (val & m)&&1);
        m = m >> 1;
    }
}

//set the bit at bitNo to value
void setBit(unsigned int& V, int bitNo, bool value){
    unsigned int mask;
    if (bitNo >= 1 && bitNo <= (sizeof(V) * 8)){
        mask = 1 << (bitNo - 1);
        V = (value)? (V | mask): (V & ~(mask)); 
    }
}
// from bit number "bitNo" in mask copies NoOfBits bits into V
void copyBits(unsigned int& V, int bitNo, int NoOfBits, unsigned int mask){
    unsigned int m;
    int i;
    if (bitNo >= 1 && NoOfBits >= 1){
        m = 1 << (bitNo - 1);
        for (i = bitNo; i < bitNo + NoOfBits && i <= (sizeof(V) * 8); i++){
            // (mask & m) >> (i - 1) give mask's bitNo-th digit
            setBit(V, i, (mask & m)>>(i-1));
            m= m << 1;
        } 
    }
}

int main(){
    unsigned int A = 0x5C;
    unsigned int M = 0x85025512;
    printf("A (Before copy): %02X\n", A);
    prnBits(A); putchar('\n');
    printf("M: %02X\n", M);
    prnBits(M); putchar('\n');
    copyBits(A,5,8,M);
    printf("A (After copy): %02X\n", A);
    prnBits(A); putchar('\n');
    return 0;
}