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    m Shorten template names. Use {{lc}} where appropriate.
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    {{cpp/utility/bitset/title | operator[]}}
    {{cpp/utility/bitset/title | operator[]}}
    {{cpp/utility/bitset/navbar}}
    {{cpp/utility/bitset/navbar}}
    {{ddcl list begin}}
    {{begin}}
    {{ddcl list item | num=1 | notes={{mark until c++11}}<br>{{mark since c++11}} |
    {{| num=1 | notes={{mark until c++11}}<br>{{mark since c++11}} |
    bool operator[]( std::size_t pos ) const;
    bool operator[]( std::size_t pos ) const;
    constexpr bool operator[]( std::size_t pos ) const;
    constexpr bool operator[]( std::size_t pos ) const;
    }}
    }}
    {{ddcl list item | num=2 |
    {{| num=2 |
    reference operator[]( std::size_t pos );
    reference operator[]( std::size_t pos );
    }}
    }}
    {{ddcl list end}}
    {{end}}


    Accesses the bit at position {{tt|pos}}. The first version returns the value of the bit, the second version returns an object of type {{c|std::bitset::reference}} that allows modification of the value.
    Accesses the bit at position {{tt|pos}}. The first version returns the value of the bit, the second version returns an object of type {{|std::bitset::reference}} that allows modification of the value.


    Unlike {{rlpf|test}}, does not throw exceptions: the behavior is undefined if {{tt|pos}} is out of bounds.
    Unlike {{rlpf|test}}, does not throw exceptions: the behavior is undefined if {{tt|pos}} is out of bounds.


    ===Parameters===
    ===Parameters===
    {{param list begin}}
    {{begin}}
    {{param list item | pos | position of the bit to return}}
    {{| pos | position of the bit to return}}
    {{param list end}}
    {{end}}


    ===Return value===
    ===Return value===
    1) the value of the requested bit
    1) the value of the requested bit


    2) an object of type {{c|std::bitset::reference}}, which allows writing to the requested bit.
    2) an object of type {{|std::bitset::reference}}, which allows writing to the requested bit.


    ===Exceptions===
    ===Exceptions===
    Line 56: Line 56:


    ===See also===
    ===See also===
    {{dcl list begin}}
    {{begin}}
    {{dcl list template | cpp/utility/bitset/dcl list test}}
    {{| cpp/utility/bitset/dcl list test}}
    {{dcl list end}}
    {{end}}


    [[de:cpp/utility/bitset/operator at]]
    [[de:cpp/utility/bitset/operator at]]

    Revision as of 04:13, 1 June 2013

     
    C++
     
    Utilities library
    General utilities
    Relational operators (deprecated in C++20)
     
    std::bitset
     
    bool operator[]( std::size_t pos ) const;
constexpr bool operator[]( std::size_t pos ) const;
    		(1) (until C++11)
    (since C++11) 
    reference operator[]( std::size_t pos );
    		(2)

    Accesses the bit at position pos. The first version returns the value of the bit, the second version returns an object of type std::bitset::reference that allows modification of the value.

    Unlike test(), does not throw exceptions: the behavior is undefined if pos is out of bounds.

    Parameters

    pos - position of the bit to return

    Return value

    1) the value of the requested bit

    2) an object of type std::bitset::reference, which allows writing to the requested bit.

    Exceptions

    None

    Example

    Run this code
    #include <iostream>
#include <bitset>

int main()
{
    std::bitset<8> b1(42);
    for (std::size_t i = 0; i < b1.size(); ++i) {
        std::cout << "b1[" << i << "]: " << b1[i] << '\n';
    }
    b1[0] = true; // modifies the first bit through bitset::refence
    std::cout << "After setting bit 0, the bitset holds " << b1 << '\n';
}

    Output: 

    b1[0]: 0
b1[1]: 1
b1[2]: 0
b1[3]: 1
b1[4]: 0
b1[5]: 1
b1[6]: 0
b1[7]: 0
After setting bit 0, the bitset holds 00101011

    See also

    		 accesses specific bit
    (public member function) [edit]