std::bitset<N>::test

bool test( size_t pos ) const;

Returns the value of the bit at the position pos.

Unlike operator[], performs a bounds check and throws std::out_of_range if pos does not correspond to a valid position in the bitset.

Parameters

pos

-

position of the bit to return

Return value

true if the requested bit is set, false otherwise.

Exceptions

std::out_of_range if pos does not correspond to a valid position within the bitset.

Example

Run this code

#include <iostream>
#include <bitset>
 
int main() 
{
    std::bitset<10> b1("1111010000");
 
    size_t idx = 0;
    while (idx < b1.size() && !b1.test(idx)) {
      ++idx;
    }
 
    if (idx < b1.size()) {
        std::cout << "first set bit at index " << idx << '\n';
    } else {
        std::cout << "no set bits\n";
    }
}

Output:

first set bit at index 4

Language
Standard Library Headers
Freestanding and hosted implementations
Named requirements
Language support library
Concepts library (C++20)
Diagnostics library
Utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

Member types
bitset::reference
Member functions
bitset::bitset
bitset::operator==bitset::operator!=
Element access
bitset::operator[]
bitset::test
bitset::allbitset::anybitset::none (C++11)
bitset::count
Capacity
bitset::size
Modifiers
bitset::operator&=bitset::operator\|=bitset::operator^=bitset::operator~
bitset::operator<<=bitset::operator>>=bitset::operator<<bitset::operator>>
bitset::set
bitset::reset
bitset::flip
Conversions
bitset::to_string
bitset::to_ulong
bitset::to_ullong (C++11)
Non-member functions
operator&operator\|operator^
operator<<operator>>
Helper classes
std::hash (C++11)

std::bitset<N>::test

Parameters

Return value

Exceptions

Example

See also