Copies the elements from the range[first, last) to another range beginning atd_first, while replacing all elements satisfying specific criteria withnew_value.

If any of the results of the expressions*first andnew_value is notwritable tod_first, the program is ill-formed.

If the source and destination ranges overlap, the behavior is undefined.

[edit]Parameters

[edit]Return value

Iterator to the element past the last element copied.

[edit]Complexity

Given\(\scriptsize N\)N asstd::distance(first, last):

[edit]Exceptions

The overloads with a template parameter namedExecutionPolicy report errors as follows:

• If execution of a function invoked as part of the algorithm throws an exception andExecutionPolicy is one of thestandard policies,std::terminate is called. For any otherExecutionPolicy, the behavior is implementation-defined.
• If the algorithm fails to allocate memory,std::bad_alloc is thrown.

[edit]Possible implementation

template<class InputIt,class OutputIt,class T>OutputIt replace_copy(InputIt first, InputIt last, OutputIt d_first,const T& old_value,const T& new_value){for(; first!= last;++first)*d_first++=(*first== old_value)? new_value:*first;return d_first;}

template<class InputIt,class OutputIt,class UnaryPred,class T=typenamestd::iterator_traits<ForwardIt>::value_type>OutputIt replace_copy_if(InputIt first, InputIt last, OutputIt d_first,                         UnaryPred p,const T& new_value){for(; first!= last;++first)*d_first++= p(*first)? new_value:*first;return d_first;}

[edit]Notes

[edit]Example

#include <algorithm>#include <complex>#include <iostream>#include <vector> void println(constauto& seq){for(constauto& e: seq)std::cout<< e<<' ';std::cout<<'\n';} int main(){std::vector<short> src{3,1,4,1,5,9,2,6,5};    println(src);std::vector<int> dst(src.size());    std::replace_copy_if(src.cbegin(), src.cend(),                         dst.begin(),[](short n){return n>5;},0);    println(dst); std::vector<std::complex<double>> src2{{1,3},{2,4},{3,5}},                                      dst2(src2.size());    println(src2);#ifdef __cpp_lib_algorithm_default_value_type        std::replace_copy_if(src2.cbegin(), src2.cend(), dst2.begin(),[](std::complex<double> z){return std::abs(z)<5;},{4,2});// Possible, since the T is deduced.#else        std::replace_copy_if(src2.cbegin(), src2.cend(), dst2.begin(),[](std::complex<double> z){return std::abs(z)<5;},std::complex<double>{4,2});#endif    println(dst2);}

3 1 4 1 5 9 2 6 5 3 1 4 1 5 0 2 0 5 (1,3) (2,4) (3,5) (4,2) (4,2) (3,5)

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

1. ↑The actual defect in the C++ standard is that the template parameterInputIterator was misspecified asIterator. This affects the type requirements because the C++ standard states that for the function templates in the algorithms library, the template type parameters whose name ends withIterator imply the type requirements of the corresponding iterator categories.

[edit]See also

• In other languages

• Deutsch
• Español
• Français
• Italiano
• 日本語
• Português
• Русский
• 中文