# How to convert a Vector to Set in C++

• Difficulty Level : Medium
• Last Updated : 01 Jun, 2022

This article shows how to convert a vector to a set in C++.

Example:

Input: vector = {1, 2, 3, 1, 1}
Output: set = {1, 2, 3}

Input: vector = {1, 2, 3, 3, 5}
Output: set = {1, 2, 3, 5}

Below are the various ways to do the required conversion:

• Method 1: Naive Solution
1. Get the vector to be converted.
2. Create an empty set, to store the result.
3. Iterate through the vector one by one, and insert each element into the set.
4. Print the resultant set.

## C++

 `// C++ program to convert``// a Vector to Set` `#include ``#include ``#include ``using` `namespace` `std;` `// Function to convert Vector to Set``set<``int``> convertToSet(vector<``int``> v)``{``    ``// Declaring the set``    ``set<``int``> s;` `    ``// Traverse the Vector``    ``for` `(``int` `x : v) {` `        ``// Insert each element``        ``// into the Set``        ``s.insert(x);``    ``}` `    ``// Return the resultant Set``    ``return` `s;``}` `// Functiont for printing the set``void` `printSet(set<``int``> s)``{` `    ``cout << ``"Set: "``;``    ``for` `(``int` `x : s) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Functiont for printing the vector``void` `printVector(vector<``int``> vec)``{` `    ``cout << ``"Vector: "``;``    ``for` `(``int` `x : vec) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Driver Code``int` `main()``{` `    ``// Vector``    ``vector<``int``> vec = { 1, 2, 3, 1, 1 };``    ``printVector(vec);` `    ``// Convert Vector to Set``    ``set<``int``> s = convertToSet(vec);` `    ``printSet(s);` `    ``return` `0;``}`

Output

```Vector: 1 2 3 1 1
Set: 1 2 3
```
• Method 2: Using Range Converter
1. Get the vector.
2. Define a set that copies all elements of the vector using 2 pointers begin and end.
3. Print the set.

## C++

 `// C++ program to convert``// a Vector to Set` `#include ``#include ``#include ``using` `namespace` `std;` `// Function to convert Vector to Set``set<``int``> convertToSet(vector<``int``> v)``{``    ``// Declaring the set``    ``// using range of vector``    ``set<``int``> s(v.begin(), v.end());` `    ``// Return the resultant Set``    ``return` `s;``}` `// Functiont for printing the set``void` `printSet(set<``int``> s)``{` `    ``cout << ``"Set: "``;``    ``for` `(``int` `x : s) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Functiont for printing the vector``void` `printVector(vector<``int``> vec)``{` `    ``cout << ``"Vector: "``;``    ``for` `(``int` `x : vec) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Driver Code``int` `main()``{` `    ``// Vector``    ``vector<``int``> vec = { 1, 2, 3, 1, 1 };``    ``printVector(vec);` `    ``// Convert Vector to Set``    ``set<``int``> s = convertToSet(vec);` `    ``printSet(s);` `    ``return` `0;``}`

Output

```Vector: 1 2 3 1 1
Set: 1 2 3
```
• Method 3: Using Copy():
1. Get the vector.
2. Define a set that copies all elements of the vector using the standard algorithm std::copy() method defined in the <algorithm> header.
3. Print the set.

Below is the implementation of the above approach:

## C++

 `// C++ program to convert``// a Vector to Set` `#include ``#include ``#include ``using` `namespace` `std;` `// Function to convert Vector to Set``set<``int``> convertToSet(vector<``int``> v)``{``    ``// Declaring the set``    ``set<``int``> s;` `    ``// Inserting the elements``    ``// of the vector in the set``    ``// using copy() method``    ``copy(` `        ``// The pointer to the beginning``        ``// of the source container``        ``v.begin(),``      ` `        ``// The pointer to the end``        ``// of the source container``        ``v.end(),` `        ``// Method of copying``        ``inserter(s, s.end()));` `    ``// Return the resultant Set``    ``return` `s;``}` `// Functiont for printing the set``void` `printSet(set<``int``> s)``{` `    ``cout << ``"Set: "``;``    ``for` `(``int` `x : s) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Functiont for printing the vector``void` `printVector(vector<``int``> vec)``{` `    ``cout << ``"Vector: "``;``    ``for` `(``int` `x : vec) {``        ``cout << x << ``" "``;``    ``}``    ``cout << endl;``}` `// Driver Code``int` `main()``{` `    ``// Vector``    ``vector<``int``> vec = { 1, 2, 3, 1, 1 };``    ``printVector(vec);` `    ``// Convert Vector to Set``    ``set<``int``> s = convertToSet(vec);` `    ``printSet(s);` `    ``return` `0;``}`

Output

```Vector: 1 2 3 1 1
Set: 1 2 3
```

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