# C++ Permutation

With its object-oriented programming (OOPs) approach, C++ offers an ideal environment for programming algorithms to permutate and generates data elements. Permutation is also referred to as an anagram. It is the rearrangement of characters or elements in a sequence to produce all possible combinations and variations.

In mathematics, a permutation is usually defined as an ordered arrangement or sequence in which a certain number of objects are selected from a certain number of elements within a given set. It can be used to compute the number of ways a particular combination of objects can be arranged or to generate all possible combinations of elements. In programming, a permutation is used to produce all possible variations of a given set of data elements.

In C++, permutation algorithms can be used to generate all possible combinations for a set of n elements, where n is the number of elements in the set. For example, if we have a set of five elements A, B, C, D and E, then the number of permutations possible is 5! (1x2x3x4 x5 = 120).

In C++, the permutation of elements can be found using various algorithms, including recursion and iteration. In this blog, we will discuss the permutation of elements in C++ with its example.

Example:

Let’s take an example to understand how you can find the permutation of elements in C++:

``````#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int main()
{
vector<int>arr = {1, 2, 3};
do
{
for (int i = 0; i<arr.size(); i++)
cout<<arr[i] << " ";
cout<<endl;
} while (next_permutation(arr.begin(), arr.end()));
return 0;
}
``````

Output:

The output of the above program will be:

``````1 2 3
1 3 2
2 1 3
2 3 1
3 1 2
3 2 1
``````

Explanation:

In the above example, we have used the next_permutation() function to find the permutation of elements in C++. The next_permutation() function is defined in the algorithm library.

The next_permutation() function takes two arguments, the start and end iterators of the sequence for which we want to find the permutation. In the above example, the arr.begin() is the start iterator and arr.end() is the end iterator.

The next_permutation() function returns true if the permutation is found and false if there are no more permutations. The function rearranges the elements in the given sequence and returns the next permutation of elements.

The do-while loop is used to find all the permutations of elements in the given sequence. The for loop is used to print the permutations.

## Conclusion:

In this blog, we have discussed the permutation of elements in C++ with example. The permutation of elements can be found using the next_permutation() function in C++. The next_permutation() function rearranges the elements in the given sequence and returns the next permutation of elements.

It is important to note that the next_permutation() function rearranges the elements in the sequence in lexicographical order, which means that the elements are rearranged in increasing order. In addition, it is also possible to write your own permutation algorithm by using recursion or iteration. The choice of method depends on the specific requirements and constraints of the problem at hand. Regardless of the method used, understanding the permutation concept and its implementation in C++ is a valuable skill for any computer science or mathematics student.

In conclusion, finding permutations is an important concept in mathematics and computer science. It is widely used in various applications, including cryptography, data analysis, and algorithms. By understanding the permutation concept and using the next_permutation() function, we can easily find permutations in C++ and apply it in various real-world applications.