Standard Template Library Programmer's Guide

• [first, last) is a valid range.

• There is enough space in the output range to store the copied values. That is, [result, result + (last-first)) is a valid range.

• result is not an iterator within the range [first, last) .

Linear. Replace_copy performs exactly last – first comparisons for equality and exactly last – first assignments.

vector V1;

V1.push_back(1);

V1.push_back(2);

V1.push_back(3);

V1.push_back(1);

vector V2(4);

replace_copy(V1.begin(), V1.end(), V2.begin(), 1, 99);

assert(V[0] == 99 && V[1] == 2 && V[2] == 3 && V[3] == 99);

copy , replace , replace_if , replace_copy_if

Category: algorithms

Component type: function

template

OutputIterator replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value)

Replace_copy_if copies elements from the range [first, last) to the range [result, result + (last-first)) , except that any element for which pred is true is not copied; new_value is copied instead. More precisely, for every integer n such that 0 <= n < last-first , replace_copy_if performs the assignment *(result+n) = new_value if pred(*(first+n)) , and *(result+n) = *(first+n) otherwise.

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

• InputIterator is a model of Input Iterator.

• OutputIterator is a model of Output Iterator.

• Predicate is a model of Predicate.

• T is convertible to Predicate 's argument type.

• T is Assignable.

• T is convertible to a type in OutputIterator 's set of value types.

• [first, last) is a valid range.

• There is enough space in the output range to store the copied values. That is, [result, result + (last-first)) is a valid range.

• result is not an iterator within the range [first, last) .

Linear. Replace_copy performs exactly last – first applications of pred and exactly last – first assignments.

Copy elements from one vector to another, replacing all negative numbers with 0 .

vector V1;

V1.push_back(1);

V1.push_back(-1);

V1.push_back(-5);

V1.push_back(2);

vector V2(4);

replace_copy_if(V1.begin(), V1.end(), V2.begin(), bind2nd(less(), 0), 0);

assert(V[0] == 1 && V[1] == 0 && V[2] == 0 && V[3] == 2);

copy , replace , replace_if , replace_copy

Category: algorithms

Component type: function

template

void fill(ForwardIterator first, ForwardIterator last, const T& value);

Fill assigns the value value to every element in the range [first, last) . That is, for every iterator i in [first, last) , it performs the assignment *i = value .

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

• ForwardIterator is a model of Forward Iterator . [1]

• ForwardIterator is mutable.

• T is a model of Assignable.

• T is convertible to Forward Iterator's value type.

• [first, last) is a valid range.

Complexity

Linear. Fill performs exactly last – first assignments.

vector V(4);

fill(V.begin(), V.end(), 137);

assert(V[0] == 137 && V[1] == 137 && V[2] == 137 && V[3] == 137);

[1] The reason that fill requires its argument to be a mutable forward iterator, rather than merely an output iterator, is that it uses a range [first, last) of iterators. There is no sensible way to describe a range of output iterators, because it is impossible to compare two output iterators for equality. The fill_n algorithm does have an interface that permits use of an output iterator.

copy , fill_n , generate , generate_n , iota

Category: algorithms

Component type: function

template

OutputIterator fill_n(OutputIterator first, Size n, const T& value);

Fill_n assigns the value value to every element in the range [first, first+n) . That is, for every iterator i in [first, first+n) , it performs the assignment *i = value . The return value is first + n .

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

• OutputIterator is a model of Output Iterator.

• Size is an integral type (either signed or unsigned).

• T is a model of Assignable.

• T is convertible to a type in OutputIterator 's set of value types.

• n >= 0 .

• There is enough space to hold n values. That is, [first, first+n) is a valid range.

Linear. Fill_n performs exactly n assignments.

vector V;

fill_n(back_inserter(V), 4, 137);

assert(V.size() == 4 && V[0] == 42 && V[1] == 42 && V[2] == 42 && V[3] == 42);

copy , fill , generate , generate_n , iota