Question

How to set the rightmost unset bit in a number in C++

Answer 1

#include <iostream>
#include <bitset>

void print_bits(unsigned int n) { 
    std::bitset<8> bits(n);
    std::cout << bits << '\n';
}

int setRightmostUnsetBit(int n) {
    if ((n & (n + 1)) == 0)
        return n;
 
    return n | (n + 1);
}
 
int main() {
    int n = 25;
 
    print_bits(n);
 
    print_bits(setRightmostUnsetBit(n));
 
    return 0;
}
 
 
 
 
/*
run:
 
00011001
00011011
 
*/

 

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