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std::list<T,Allocator>::assign

void assign( size_type count, const T& value );	(1)
template< class InputIt > void assign( InputIt first, InputIt last );	(2)
void assign( std::initializer_list<T> ilist );	(3)	(since C++11)

Replaces the contents of the container.

1) Replaces the contents with count copies of value value

2) Replaces the contents with copies of those in the range [first, last). The behavior is undefined if either argument is an iterator into *this.

This overload has the same effect as overload (1) if `InputIt` is an integral type.	(until C++11)
This overload participates in overload resolution only if `InputIt` satisfies LegacyInputIterator.	(since C++11)

3) Replaces the contents with the elements from the initializer list ilist.

All iterators, pointers and references to the elements of the container are invalidated.

Parameters

count	-	the new size of the container
value	-	the value to initialize elements of the container with
first, last	-	the range to copy the elements from
ilist	-	initializer list to copy the values from

Complexity

1) Linear in count

2) Linear in distance between first and last

3) Linear in ilist.size()

Example

The following code uses assign to add several characters to a std::list<char>:

#include <list>
#include <iostream>
#include <string>
 
int main()
{
    std::list<char> characters;
 
    auto print_list = [&]()
    {
        for (char c : characters)
            std::cout << c << ' ';
        std::cout << '\n';  
    };
 
    characters.assign(5, 'a');
    print_list();
 
    const std::string extra(6, 'b');
    characters.assign(extra.begin(), extra.end());
    print_list();
 
    characters.assign({'C', '+', '+', '1', '1'});
    print_list();
}

Output:

a a a a a 
b b b b b b 
C + + 1 1

Defect reports

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

DR	Applied to	Behavior as published	Correct behavior
LWG 320	C++98	the replacement operation was defined as erasing all existing elements followed by inserting the given elements	removed the definition

std::list<T,Allocator>::assign

Parameters

Complexity

Example

Defect reports

See also