Selection Sort Program Using Cpp

Source Code:

#include <iostream>
using namespace std;
void selectionSort(int arr[], int n)
{  // starting of function
    int i, j, min;  // declaration of variables
    int temp;  // temp variable for swapping values
    for (i = 0; i < n-1; i++)  // outter loop
    {
        min = i;  // setting boundry of un-sorted array
        for (j = i+1; j < n; j++)  // inner loop
        if (arr[j] < arr[min])  // checking order of element
            min = j;
        // These lines of code will swap min value with next index of sorted array
        temp = arr[min];
            arr[min] = arr[i];
            arr[i] = temp; 
    }   // ending of outter loop
}  // ending of function
int main()
{
    int i;  // counter variable for printing array values
    int arr[] = {97,55,12,98,33,67,17,49};  //array initialization
    int n = sizeof(arr)/sizeof(arr[0]);  // calculating no of elements
    cout<<"Print Unsorted array: \n";
        for (i = 0; i < n; i++) {  // printing array values before sort
        cout << arr[i] << " ";

        }
        cout<<endl;
        selectionSort(arr, n);  // function call for sorting
    cout<<"Print Sorted array: \n";
        for (i = 0; i < n; i++) {  // printing array values after sort
        cout << arr[i] << " ";

        }
    cout << endl;
    return 0;
}

Output:

Working:

In this program example we have use a function named as selectionSort for implementation of algorithm. We have declare here four variables of int data type. The detail of these variables is provided as below.

After declaration process we have used nested loop for complete sorting process. The outter loop will set first counter variable value as 0 and go until N-1. In inner loop the entire logic is implemented we have set minimum index as the i and then traverse array from i+1 to N to find out if any element is also smaller than the already set minimum index.

Here in if statement we have used  <  symbol because we are going to sort array in Ascending order. Alternatively we have to use  >  symbol if we want to sort data in Descending order.

Finally in main() function we have initialized an array with 8 elements and also declare a variable as counter variable. In main function we print array elements before and after sorting function call. We have first print array elements and then call selectionSort function and after sorting we again print elements of array.