The one_of_equal() function in C++ boost library is found under the header ‘boost/algorithm/cxx11/one_of.hpp’ which tests if exactly one of the elements of a sequence against the value passed is same. It takes a sequence and a value, and returns true if the exactly one of the elements are same in the sequence to the value passed.
bool one_of_equal ( InputIterator first, InputIterator last, const &value)
bool one_of_equal ( const Range &R, const &value)
Parameters: The function accepts parameters as described below:
- first: It specifies the input iterators to the initial positions in a sequence.
- second: It specifies the input iterators to the final positions in a sequence.
- value: It specifies a value which is to be checked against for one the elements of the sequence.
- R: It is the complete sequence.
Return Value: The function returns true if exactly one of the elements of the sequence is equal to value, else it returns false.
Below is the implementation of the above approach:
exactly one element is 1
exactly one element is not 4