C++ Vector emplace() function

by Online Tutorials Library July 22, 2022

C++ Vector emplace()

This function inserts a new element just before the position pos and size of the vector container increases.

Syntax

Consider a vector ‘v’. Syntax would be:

Parameter

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

args: Arguments forwarded to construct the new element.

Return value

It returns an iterator to the newly inserted element.

Example 1

Let’s see a simple example.

  #include <iostream>  #include<vector>  using namespace std;  int main()  {  vector<int> v{1,2,3,4,5};  cout<<“Elements of vector v are :”;  for(int i=0;i<v.size();i++)  cout<<v[i]<<” “;  cout<<‘n’;  cout<<“After adding two elements, elements are :”;  vector<int>::iterator it=v.emplace(v.begin()+2,8);  v.emplace(it,9);  for(int i=0;i<v.size();i++)  cout<<v[i]<<” “;  return 0;  }  

Output:

Elements of vector v are :1 2 3 4 5  After adding two elements, elements are :1 2 9 8 3 4 5

In this example, size of the vector container increases using emplace() function.

Example 2

Let’s see a simpleanother example.

  #include <iostream>  #include<vector>  using namespace std;  int main()  {  vector<string> v{“mango”,”apple”,”banana”};  v.emplace(v.begin()+2,”strawberry”);  for(int i=0;i<v.size();i++)  std::cout<< v[i] << ” “;  return 0;  }  

Output:

Mango apple strawberry banana

In this example, the size of the vector container increases by adding new string into the vector using emplace() function.

Next TopicC++ Vector

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