Module: Standard C++ Library Library: Algorithms
Function
Algorithm that assigns the same value to the elements in a given range
#include <algorithm>
namespace std {
template <class ForwardIterator, class T>
void fill(ForwardIterator start, ForwardIterator finish,
const T& value);
template <class OutputIterator, class Size, class T>
void fill_n(OutputIterator start, Size n, const T& value);
}
The fill() and fill_n() algorithms are used to assign a value to the elements in a sequence. fill() assigns the value to all the elements designated by iterators in the range [start, finish).
The fill_n() algorithm assigns the value to all the elements designated by iterators in the range [start, start + n). fill_n() assumes that all iterators in the range [start, start + n) are dereferenceable, unless start is an insert iterator.
Type T must be Assignable, and Size must be convertible to an integral type.
fill() makes exactly finish - start assignments, and fill_n() makes exactly n assignments.
//
// fill.cpp
//
#include <algorithm>
#include <iostream>
#include <vector>
int main ()
{
// Typedef for convenience.
typedef std::vector<int, std::allocator<int> > vector;
const vector::value_type arr[] = { 1, 2, 3, 4 };
// Set up two vectors.
vector v1(arr, arr + sizeof arr / sizeof *arr);
vector v2(v1.begin (), v1.end ());
// Set up one empty vector.
vector v3;
// Fill all of v1 with 9.
std::fill(v1.begin (), v1.end (), 9);
// Fill first 3 of v2 with 7.
std::fill_n(v2.begin (), 3, 7);
// Use insert iterator to fill v3 with 5 11's.
std::fill_n(std::back_inserter (v3), 5, 11);
// Copy all three to cout.
std::ostream_iterator<vector::value_type, char,
std::char_traits<char> > out(std::cout, " ");
std::copy(v1.begin (), v1.end (), out);
std::cout << std::endl;
std::copy(v2.begin (), v2.end (), out);
std::cout << std::endl;
std::copy(v3.begin (), v3.end (), out);
std::cout << std::endl;
// Fill cout with 3 5's.
std::fill_n(out, 3, 5);
std::cout << std::endl;
return 0;
}
Program Output
9 9 9 9 7 7 7 4 11 11 11 11 11 5 5 5
ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.2.5
Copyright (c) 1994-2006 Rogue Wave Software, a Quovadx Division.
Licensed under the Apache License, Version 2.0.
Contact Rogue Wave about documentation or support issues. You can also seek help from other developers through the Apache stdcxx community (see below).