How is the bitset used in c++?

1 year ago
Jackson Davis
3 minutes

In C++, std::bitset is a class for handling bit operations that can store and manipulate fixed-length sequences of bits.

Here is how to use std::bitset:

  1. Include header file: First of all, in order to use std::bitset, you need to include the header file.
  2. Creating objects: std::bitset objects can be created in the following ways:
    std::bitset var; // Creates a bitset object of length N, with all bits set to 0 by default
    std::bitset var(value); // Creates a bitset object of length N and initializes it to the given integer value
    std::bitset var(string); // Creates a bitset object of length N and initializes it with the given binary string
  3. Among them, N represents the length of the bitset.
  4. Accessing and modifying bits: you can use the [] operator to access and modify bits in a bitset.
    var[pos] = value; // set bit at position ‘pos’ to ‘value’
    value = var[pos]; // get the value of bit at position ‘pos’
  5. Member functions: std::bitset also provides some member functions for performing bit operations, as follows:
  6. size(): Returns the length of the bitset.
  7. count(): returns the number of bits that have been set to 1 in the bitset.
  8. any(): Checks if at least one bit is set to 1 in the bitset.
  9. none() function checks if all bits in the bitset are set to 0.
  10. all(): Checks if all bits in the bitset are set to 1.
  11. flip(): invert all bits in the bitset.
  12. reset(): reset all bits in the bitset to 0.
  13. set(): sets all bits in the bitset to 1.
  14. Check if the bit at position pos is set to 1.
  15. Bitwise operations: std::bitset also supports bitwise operators such as AND, OR, XOR, etc. as shown below:
  16. ” &: Bitwise AND operator.”
  17. Bitwise OR operator.
  18. ^: Bitwise XOR operator.
  19. ~: Bitwise NOT operator.
  20. You can convert it to a binary string using the to_string() function of the std::bitset object, or output it using the cout output operator of the std::bitset object.

The code example is shown below:

#include <bitset>
#include <iostream>

int main() {
    std::bitset<8> bits; // 创建一个长度为8的bitset对象，默认所有位都设置为0
    std::cout << bits << std::endl; // 输出: 00000000

    bits.set(3); // 将位3设置为1
    std::cout << bits << std::endl; // 输出: 00001000

    bits.flip(); // 翻转所有位
    std::cout << bits << std::endl; // 输出: 11110111

    bits.reset(); // 将所有位重置为0
    std::cout << bits << std::endl; // 输出: 00000000

    return 0;
}

The above code creates a bitset object with a length of 8, performs some operations on its bits, and prints the results.

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