bitset all() function in C++ STL

The bitset::all() is a built-in function in C++ STL which returns True if all bits are set in the binary representation of a number if it is initialized in the bitset. It returns False if all the bits are not set.

Syntax:

bool bitset_name.all() 

Parameter: This function does not accepts any parameter.

Return Value: The function returns a boolean value. The boolean value returned is true if all the bits are set, else the returned value is false,

Below programs illustrates the bitset::all() function.

Program 1:

// CPP program to illustrate the
// bitset::all() function
#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Initialization of bitset
    bitset<4> b1(string("1100"));
    bitset<6> b2(string("111111"));

    // Function that checks if all
    // the bits are set or not
    bool result1 = b1.all();
    if (result1)
        cout << b1 << " has all bits set"
             << endl;
    else
        cout << b1 << " does not have all bits set"
             << endl;

    // Function that checks if all
    // the bits are set or not
    bool result2 = b2.all();
    if (result2)
        cout << b2 << " has all bits set"
             << endl;
    else
        cout << b2 << " does not have all bits set"
             << endl;

    return 0;
}

Output:

1100 does not have all bits set
111111 has all bits set

Program 2:

// CPP program to illustrate the
// bitset::all() function
// when the input is as a number

#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Initialization of bitset
    bitset<2> b1(3);
    bitset<3> b2(5);

    // Function that checks if all
    // the bits are set or not
    bool result1 = b1.all();
    if (result1)
        cout << b1 << " has all bits set"
             << endl;
    else
        cout << b1 << " does not have all bits set"
             << endl;

    // Function that checks if all
    // the bits are set or not
    bool result2 = b2.all();
    if (result2)
        cout << b2 << " has all bits set"
             << endl;
    else
        cout << b2 << " does not have all bits set"
             << endl;

    return 0;
}

Output:

11 has all bits set
101 does not have all bits set