To set all the bits in a bitset to 1, we can make use of the set() member function provided by the bitset class. The set() function sets all the bits in the bitset to 1.

Here is an example code snippet that demonstrates setting all the bits in a bitset to 1:

#include <iostream>
#include <bitset>

int main() {
    const size_t size = 8; // number of bits in the bitset
    std::bitset<size> bitset;

    std::cout << "Before setting: " << bitset << std::endl;
  
    bitset.set(); // set all bits to 1
  
    std::cout << "After setting: " << bitset << std::endl;
  
    return 0;
}

In this example, we first define a bitset of size 8. We then print the bitset before setting all the bits and observe that all bits are initially set to 0. After calling set(), all bits in the bitset are set to 1. We then print the bitset again to verify the change.

When you run the code, you should see the following output:

Before setting: 00000000
After setting: 11111111

By using the set() function of std::bitset, we can easily set all the bits in a bitset to 1. This can be useful in various scenarios where we need to initialize a bitset with all bits set to a specific value.