Defined in header <algorithm> | ||
---|---|---|
template< class ForwardIt, class T > void replace( ForwardIt first, ForwardIt last, const T& old_value, const T& new_value ); | (1) | |
template< class ExecutionPolicy, class ForwardIt, class T > void replace( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, const T& old_value, const T& new_value ); | (2) | (since C++17) |
template< class ForwardIt, class UnaryPredicate, class T > void replace_if( ForwardIt first, ForwardIt last, UnaryPredicate p, const T& new_value ); | (3) | |
template< class ExecutionPolicy, class ForwardIt, class UnaryPredicate, class T > void replace_if( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPredicate p, const T& new_value ); | (4) | (since C++17) |
Replaces all elements satisfying specific criteria with new_value
in the range [first, last)
.
old_value
.p
returns true
.policy
. These overloads do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>>
is truefirst, last | - | the range of elements to process |
old_value | - | the value of elements to replace |
policy | - | the execution policy to use. See execution policy for details. |
p | - | unary predicate which returns true if the element value should be replaced. The signature of the predicate function should be equivalent to the following:
The signature does not need to have |
new_value | - | the value to use as replacement |
Type requirements | ||
-ForwardIt must meet the requirements of ForwardIterator . |
||
-UnaryPredicate must meet the requirements of Predicate . |
(none).
Exactly last - first
applications of the predicate.
The overloads with a template parameter named ExecutionPolicy
report errors as follows:
ExecutionPolicy
is one of the three standard policies, std::terminate
is called. For any other ExecutionPolicy
, the behavior is implementation-defined. std::bad_alloc
is thrown. First version |
---|
Second version |
The following code at first replaces all occurrences of 8
with 88
in a vector of integers. Then it replaces all values less than 5
with 55.
#include <algorithm> #include <array> #include <iostream> #include <functional> int main() { std::array<int, 10> s{5, 7, 4, 2, 8, 6, 1, 9, 0, 3}; std::replace(s.begin(), s.end(), 8, 88); for (int a : s) { std::cout << a << " "; } std::cout << '\n'; std::replace_if(s.begin(), s.end(), std::bind(std::less<int>(), std::placeholders::_1, 5), 55); for (int a : s) { std::cout << a << " "; } std::cout << '\n'; }
Output:
copies a range, replacing elements satisfying specific criteria with another value (function template) |
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