Java Program for Selection Sort

Last Updated : 10 Jan, 2024

The selection sort algorithm sorts an array by repeatedly finding the minimum element (considering ascending order) from the unsorted part and putting it at the beginning.

Basic Principle of Selection Sort

The algorithm works by maintaining two subarrays in a given array:

The subarray is already sorted.

Remaining subarray which is unsorted.

In every iteration of the selection sort, the minimum element (considering ascending order) from the unsorted subarray is picked and moved to the sorted subarray.

Java Selection Sort

Algorithm for Selection Sort

Implementation of Selection Sort in Java is mentioned below:

Step 1: Array arr with N size
Step 2: Initialise i=0
Step 3: If(i<N-1) Check for any element arr[j] where j>i and arr[j]<arr[i] then Swap arr[i] and arr[j]
Step 4: i=i+1 and Goto Step 3
Step 5: Exit

Program to Implement Selection Sort Java

Java

// Java program for implementation 
// of Selection Sort 
  
// Driver Class 
class SelectionSort { 
    void sort(int arr[]) 
    { 
        int n = arr.length; 
  
        // One by one move boundary of unsorted subarray 
        for (int i = 0; i < n - 1; i++) { 
            // Find the minimum element in unsorted array 
            int min_idx = i; 
            for (int j = i + 1; j < n; j++) { 
                if (arr[j] < arr[min_idx]) 
                    min_idx = j; 
            } 
  
            // Swap the found minimum element with the first 
            // element 
            int temp = arr[min_idx]; 
            arr[min_idx] = arr[i]; 
            arr[i] = temp; 
        } 
    } 
  
    // Prints the array 
    void printArray(int arr[]) 
    { 
        int n = arr.length; 
        for (int i = 0; i < n; ++i) 
            System.out.print(arr[i] + " "); 
        System.out.println(); 
    } 
  
    // main function 
    public static void main(String args[]) 
    { 
        SelectionSort ob = new SelectionSort(); 
        int arr[] = { 64, 25, 12, 22, 11 }; 
  
        ob.sort(arr); 
        System.out.println("Sorted array"); 
        ob.printArray(arr); 
    } 
}