Swap two elements of 1D array in C++
In this tutorial, we will learn how to swap two elements in a one-dimensional array. This we will see through either using a manual swap function or a built-in swap function in C++. Hope you will like this tutorial. Let’s get started.
Swap two elements of a 1D array in C++
To swap two elements in a 1D array we can do it in two ways. First, we will do it manually, and second, we will do using the built-in C++ function that swap() method.
Suppose we are given a 1D array such as an array having size 6 and we want to swap two elements having values 1 and 3 so that the array becomes sorted in decreasing order.
array[6] = {5,4,1,2,3,0}
After swap we will have array[6] = {5,4,3,2,1,0}.
Steps to Swap two elements.
- First, create a temporary variable such as temp and store the value of that particular index.
- Then, the value of the second index in the first index.
- Lastly, store the temp value in the second index.
Let’s understand with example code. Then it will be very clear.
#include <iostream> using namespace std; void printArr (int arr[], int length) { for(int i = 0; i < length; i++) { cout << arr[i] << " "; } cout << endl; } int main() { // declare array const int length = 5; int arr[length] = {5, 2, 3, 4, 1}; // temp variable in swapping int temp; cout << "Original array: "; printArr(arr, length); // swapping second and fourth element temp = arr[1]; arr[1] = arr[3]; arr[3] = temp; cout << "Array with second and fourth element swapped and sorted: "; printArr(arr, length); return 0; }
OUTPUT: Original array: 5 2 3 4 1 Array with second and fourth element swapped and sorted: 5 4 3 2 1
Now we will see using the built-in swap() function in C++. This function helps in swapping two elements without using a third variable such as the temp variable as we used in the above case.
Syntax :
void swap(int var1, int var2)
#include <iostream> using namespace std; void printArr (int arr[], int size) { for(int i = 0; i < size; i++) { cout << arr[i] << " "; } cout << endl; } int main() { const int size = 5; int arr[size] = {5, 2, 3, 4, 1}; cout << "Original array: "; printArr(arr, size); swap(arr[1], arr[3]); // built-in swap() method cout << "Array with second and fourth element swapped: "; printArr(arr, size); return 0; }
OUTPUT:
Original array: 5 2 3 4 1
Array with second and fourth element swapped: 5 4 3 2 1
Hope you liked this tutorial. Keep Learning !!!!
Also Read: C++ Null Pointers with examples
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