Java code for Bubble Sort, Selection Sort, Insertion Sort and Quick Sort

/*
Program to sort an array, entered by the user, in ascending order
using Bubble Sort, Selection Sort, Insertion Sort or Quick Sort as
per user's choice.
*/

import java.io.*;
class sortArray
{
int a[];
int n;
static BufferedReader br = new BufferedReader(new
InputStreamReader(System.in));
public sortArray(int nn) // Constructor
{
a = new int[nn];
n = nn;
}
public static void main(String args[]) throws IOException
{
System.out.print("\nEnter the size of the array : ");
int nn = Integer.parseInt(br.readLine());
sortArray call = new sortArray(nn);
// Read array from user
System.out.println("\nEnter " +nn +" elements :");
call.readArray();
// Ask for choosing the sorting technique
System.out.println("Choose Sorting Technique :\n");
System.out.println("1 : Bubble Sort");
System.out.println("2 : Selection Sort");
System.out.println("3 : Insertion Sort");
System.out.println("4 : Quick Sort");
System.out.print("\nYour Choice : ");
int choice = Integer.parseInt(br.readLine());
switch(choice)
{
case 1:
call.bubbleSort();
break;
case 2:
call.selectionSort();
break;
case 3:
call.insertionSort();
break;
case 4:
call.quickSort();
break;
default :
System.out.println("\nInvalid Choice !");
System.exit(1);
break;
}
call.display(); // Print the sorted array
}
public void readArray() throws IOException
{
for(int i=0;i<n;i++)
a[i] = Integer.parseInt(br.readLine());
}
public void bubbleSort()
{
int t;
for(int i=0;i<n-1;i++)
{
for(int j=0;j<n-1-i;j++)
{
if(a[j]>a[j+1])
{
t = a[j];
a[j] = a[j+1];
a[j+1] = t;
}
}
}
}
public void selectionSort()
{
int t, min;
for(int i=0;i<n-1;i++)
{
min = i;
for(int j=i+1;j<n;j++)
2{
if(a[min]>a[j])
min = j;
}
if(min!=i)
{
t = a[min];
a[min] = a[i];
a[i] = t;
}
}
}
public void insertionSort()
{
int t,j;
for(int i=1;i<n;i++)
{
j = i-1;
t = a[i];
while(t<a[j] && j>=0)
{
a[j+1] = a[j];
j--;
}
a[j+1] = t;
}
}
public void quickSort()
{
int t;
for(int i=0;i<n-1;i++)
{
for(int j=i+1;j<n;j++)
{
if(a[i]>a[j])
{
t = a[i];
a[i] = a[j];
a[j] = t;
}
}
}
}
public void display()
{
System.out.println("\nSorted Array :");
for(int i=0;i<n;i++)
System.out.println(a[i]);
3}
}

/**
* Algorithm for Selection Sort :
* ----------------------------
* 1. Start
* 2. Construct a single-dimensional array of appropriate size.
* 3. Fill the array with data entries.
* 4. Using selection sort technique bring the smallest number to the
first unsorted position of the array.
* 5. Repeat step 4 till the entire array is sorted.
* 6. Print the sorted array.
* 7. End
*
* Algorithm for Bubble Sort :
* ----------------------------
* 1. Start
* 2. Construct a single-dimensional array of appropriate size.
* 3. Fill the array with data entries.
* 4. Using bubble sort technique push the largest number to the last
unsorted position of the array.
* 5. Repeat step 4 till the entire array is sorted.
* 6. Print the sorted array.
* 7. End
*
* Algorithm for Insertion Sort :
* ----------------------------
* 1. Start
* 2. Construct a single-dimensional array of appropriate size.
* 3. Fill the array with data entries.
* 4. Using insertion sort technique push the largest number to the
last unsorted position of the array.
* 5. Repeat step 4 till the entire array is sorted.
* 6. Print the sorted array.
* 7. End
*
* Algorithm for Quick Sort :
* ----------------------------
* 1. Start
* 2. Construct a single-dimensional array of appropriate size.
* 3. Fill the array with data entries.
* 4. Using quick sort technique push the largest number to the last
unsorted position of the array.
* 5. Repeat step 4 till the entire array is sorted.
* 6. Print the sorted array.
* 7. End
*/

/*
OUTPUT :
------
Enter the size of the array : 5
Enter 5 elements :
12
54
65
32
23
Choose Sorting Technique :
1
2
3
4
:
:
:
:
Bubble Sort
Selection Sort
Insertion Sort
Quick Sort
Your Choice : 1
Sorted Array :
12
23
32
54
65
*/