C++ <vector> - assign() Function
The C++ vector::assign function is used to assign new values to the vector, replacing its old values, and modifying its size if necessary.
Syntax
//range version template <class InputIterator> void assign (InputIterator first, InputIterator last); //fill version void assign (size_type n, const value_type& val);
//range version template <class InputIterator> void assign (InputIterator first, InputIterator last); //fill version void assign (size_type n, const value_type& val); //initializer list version void assign (initializer_list<value_type> ilist);
Parameters
first |
Specify the starting position of InputIterator. The range used by InputIterator is [first,last). |
last |
Specify the last position of InputIterator. The range used by InputIterator is [first,last). |
n |
Specify new size of the vector. |
val |
Specify the value to fill the vector with. Each of the vector will be initialized to a copy of this value. |
ilist |
Specify the initializer_list object. |
Return Value
None.
Time Complexity
Linear i.e, Θ(n)
Example:
In the example below, the vector::assign function is used to assign new values to the given vector, replacing its old values.
#include <iostream>
#include <vector>
using namespace std;
int main (){
vector<int> vec1;
vector<int> vec2;
vector<int> vec3;
//using fill version - size 5 with value 10
vec1.assign(5, 10);
//using range version
vector<int>::iterator it;
it = vec1.begin();
vec2.assign(it, it+3);
//using initializer list version
int MyList[] = {10, 20, 30, 40, 50};
vec3.assign(MyList, MyList+3);
cout<<"vec1 contains: ";
for(it = vec1.begin(); it != vec1.end(); ++it)
cout<<*it<<" ";
cout<<"\nvec2 contains: ";
for(it = vec2.begin(); it != vec2.end(); ++it)
cout<<*it<<" ";
cout<<"\nvec3 contains: ";
for(it = vec3.begin(); it != vec3.end(); ++it)
cout<<*it<<" ";
return 0;
}
The output of the above code will be:
vec1 contains: 10 10 10 10 10 vec2 contains: 10 10 10 vec3 contains: 10 20 30
❮ C++ <vector> Library
