operator==,!=,<,<=,>,>=std::valarray
template< class T > valarray<bool> operator==( const valarray<T>& lhs, const valarray<T>& rhs ); |
(1) | |
template< class T > valarray<bool> operator==( const T& lhsv, const valarray<T>& rhs ); |
(2) | |
template< class T > valarray<bool> operator==( const valarray<T>& lhs, const T& rhsv ); |
(3) | |
Compares each value within the numeric array with another value.
lhs
and rhs
The behavior is undefined if size() != v.size()
lhsv
and the corresponding value of rhs
.lhs
and rhsv
.Parameters
lhs, rhs | - | numeric arrays to compare |
lhsv, rhsv | - | values to compare to each element within a numeric array |
Return value
A numeric array of bool containing comparison results of corresponding elements.
Exceptions
(none)
Notes
Each of the operators can only be instantiated if the following requirements are met:
- The indicated operator can be applied to type
T
- The result value can be unambiguously converted to
bool
.
- The indicated operator can be applied to type
The function can be implemented with the return type different from std::valarray. In this case, the replacement type has the following properties:
- All const member functions of std::valarray are provided.
- std::valarray, std::slice_array, std::gslice_array, std::mask_array and std::indirect_array can be constructed from the replacement type.
- All functions accepting an argument of type const std::valarray& except begin() and end() (since C++14) should also accept the replacement type.
- All functions accepting two arguments of type const std::valarray& should accept every combination of const std::valarray& and the replacement type.
- The return type does not add more than two levels of template nesting over the most deeply-nested argument type.
Example
#include <iostream> #include <valarray> int main() { // zero all negatives in a valarray std::valarray<int> v = {1, -1, 0, -3, 10, -1, -2}; std::cout << "Before: "; for(auto n: v) std::cout << n << ' '; std::cout << '\n'; v[v < 0] = 0; std::cout << "After: "; for(auto n: v) std::cout << n << ' '; std::cout << '\n'; // convert the vector<bool> result of == to a single bool std::valarray<int> a = {1,2,3}; std::valarray<int> b = {2,4,6}; std::cout << "2*a == b is " << std::boolalpha << (2*a == b).min() << '\n'; }
Output:
Before: 1 -1 0 -3 10 -1 -2 After: 1 0 0 0 10 0 0 2*a == b is true