Bit manipulation is a powerful technique in programming, especially when working with low-level operations or optimizing code. The C++ Standard Library provides the std::bitset class, which is a convenient wrapper to manipulate sequences of bits. However, by default, the std::bitset class assumes that the bits are contiguous. But what if we want to perform bit operations on non-contiguous bits? In this blog post, we will explore how to achieve this in C++ using std::bitset.

The Problem

Let’s say we have a std::bitset of size 8, and we want to perform bit operations on bits at indices 1, 3, and 6. By default, std::bitset does not provide a direct way to perform operations on non-contiguous bits.

The Solution

To manipulate non-contiguous bits, we can use the logical bitwise operators (&, |, ^) in conjunction with the std::bitset::test() and std::bitset::set() functions.

Here’s an example code snippet to demonstrate how to perform bit operations on non-contiguous bits using std::bitset:

#include <bitset>
#include <iostream>

int main() {
    std::bitset<8> bitset;

    // Set the bits at indices 1, 3, and 6
    bitset.set(1);
    bitset.set(3);
    bitset.set(6);

    // Perform bit operations on the non-contiguous bits
    std::bitset<8> operationResult = (bitset.test(1) & bitset.test(3)) | bitset.test(6);

    std::cout << "Result: " << operationResult << std::endl;

    return 0;
}

In the above code, we create a std::bitset of size 8 and set the bits at indices 1, 3, and 6 using std::bitset::set(). Then, we perform bit operations on these non-contiguous bits using the logical bitwise operators. Finally, we print the result to the console.

Conclusion

Although the std::bitset class in C++ assumes contiguous bits by default, we can still perform bit operations on non-contiguous bits by combining logical bitwise operators with std::bitset::test() and std::bitset::set(). By leveraging these techniques, we can manipulate specific bits in a std::bitset without the constraint of contiguity.

#bitmanipulation #bitset #cplusplus