How to remove vector nth element in C++? [SOLVED]

Introduction

In this article we will learn c++ vector remove nth element. Vectors are a part of the c++ STL library. They are containers but can change memory at runtime. Which can be very useful in memory and space management of programs.

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Vectors

Vectors are a part of Standard Template Library (STL) in C++ which is a general purpose library used to store and retrieve continuous data. Vectors are similar to arrays but they change their size during runtime. C++ and Java are one of the few general purpose high level languages which help in memory management.

How to initialize a vector ?

Include the vector library

#include<vector>

Initialize vector

vector<int> v;

Vectors have some built in functions, some most important ones are :

• push_back() to insert data at the end.
• begin() shows the starting point of the vector.
• end() shows the end of the vector.
• size() returns the size of the vector.
• capacity() shows the capacity of the vector.
• resize() it resize the vector to the desirable size.

Lets look at a code example of how all these functions work

// c++ vector remove nth element
#include <vector>
#include <iostream>
using namespace std;
int main()
{
vector<int> v;
int i;
for (i = 0; i < 10; i++)
v.push_back(i);
v.erase(v.begin() + 5);
for (i = 0; i < v.size(); i++)
cout << v[i] << " ";
cout << endl;
//size of vector
cout << "size of vector: " << v.size() << endl;
//capacity of vector
cout << "capacity of vector: " << v.capacity() << endl;
//resize vector
v.resize(5);
cout << "size of vector: " << v.size() << endl;
//begin
cout << "begin: " << *v.begin() << endl;
//end
cout << "end: " << *v.end() << endl;
//max size
cout << "max size: " << v.max_size() << endl;
return 0;
}

Output of this code is :

0 1 2 3 4 6 7 8 9
size of vector: 9
capacity of vector: 16
size of vector: 5
begin: 0
end: 6
max size: 2305843009213693951

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Solution: c++ vector remove nth element

We will now look at how c++ vector remove nth element . one way is to add the nth element to the start and erase that element.

Lets look at the code :

// c++ vector remove nth element
#include <vector>
#include <iostream>
using namespace std;
int main()
{
vector<int> v;
int i;
for (i = 0; i < 10; i++)
v.push_back(i);
for (i = 0; i < v.size(); i++)
cout << v[i] << " ";
cout << endl;
// // remove the nth element
int n;
cout << "Enter the element to be removed: ";
cin >> n;
v.erase(v.begin() + n);
for (i = 0; i < v.size(); i++)
cout << v[i] << " ";
return 0;

}

Output :

The vector is 0 1 2 3 4 5 6 7 8 9 
Enter the element to be removed: 4
0 1 2 3 5 6 7 8 9

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Conclusion

In this article we learned c++ vector removes nth element. How we can add elements to a vector, how we can access it, how we can erase an element to a vector. We studied the in-built functions of the vectors like size, capacity, begin, and end.

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Further Reading

Vector Operations
Vectors