C++ Program to Implement Selection Sort
In the selection sort technique, the list is divided into two parts. In one part all elements are sorted and in another part the items are unsorted. At first we take the maximum or minimum data from the array. After getting the data (say minimum) we place it at the beginning of the list by replacing the data of first place with the minimum data. After performing the array is getting smaller. Thus this sorting technique is done.
The complexity of Selection Sort Technique
Time Complexity: O(n2)
Space Complexity: O(1)
Input − The unsorted list: 5 9 7 23 78 20
Output − Array after Sorting: 5 7 9 20 23 78
Algorithm
selectionSort(array, size)
Input: An array of data, and the total number in the array
Output: The sorted Array
Begin
for i := 0 to size-2 do //find minimum from ith location to size
iMin := i;
for j:= i+1 to size – 1 do
if array[j] < array[iMin] then
iMin := j
done
swap array[i] with array[iMin].
done
End
Example Code
#include<iostream>
using namespace std;
void swapping(int &a, int &b) { //swap the content of a and b
int temp;
temp = a;
a = b;
b = temp;
}
void display(int *array, int size) {
for(int i = 0; i<size; i++)
cout << array[i] << " ";
cout << endl;
}
void selectionSort(int *array, int size) {
int i, j, imin;
for(i = 0; i<size-1; i++) {
imin = i; //get index of minimum data
for(j = i+1; j<size; j++)
if(array[j] < array[imin])
imin = j;
//placing in correct position
swap(array[i], array[imin]);
}
}
int main() {
int n;
cout << "Enter the number of elements: ";
cin >> n;
int arr[n]; //create an array with given number of elements
cout << "Enter elements:" << endl;
for(int i = 0; i<n; i++) {
cin >> arr[i];
}
cout << "Array before Sorting: ";
display(arr, n);
selectionSort(arr, n);
cout << "Array after Sorting: ";
display(arr, n);
}Output
Enter the number of elements: 6
Enter elements:
5 9 7 23 78 20
Array before Sorting: 5 9 7 23 78 20
Array after Sorting: 5 7 9 20 23 78
Published on 14-Mar-2019 18:21:35
