C++ List emplace() Usage and Example

C++ List (List)

C ++ The List emplace() function inserts a new element at the specified position, and the size of the list increases by one.

Syntax

iterator emplace(iterator pos, value_type val);

Parameter

pos：It defines the position where the new element is to be inserted.

val：The value to be inserted at the specified position.

Return Value

It returns an iterator pointing to the newly constructed element.

Example1

Let's look at a simple example of inserting a new element between the list elements.

Example

#include<iostream>
#include<list>
using namespace std;
int main()
{
　　list<char> li={'j','v','a'};
　　list<char>::iterator itr=li.begin();
　　++itr;
　　li.emplace(itr, 'a');
　　for(itr=li.begin();itr!=li.end();++itr)
　　cout <<*itr;
　　return 0;
}

Output:

java

In this example, the emplace() function added a new character at the second position

Example2

Let's look at a simple example of adding a new element to the end of the list.

Example

#include<iostream>
#include<list>
using namespace std;
int main()
{
　　list<string> li={"java","is","a"};
　　list<string>::iterator itr;
　　li.emplace(li.end(),"programming language");
　for(itr=li.begin();itr!=li.end();++itr)
　　cout <<*itr << "  ";
　　return 0;
　
}

Output:

java is a programming language

In this example, the emplace() function adds a new string at the end of the list, that is, 'programming language'.

C++ List (List)