Java Program to implement Associate Array

Code:

import java.util.Scanner;
import java.util.HashMap;

/** class AssociateArray */
class AssociateArray
{
    private HashMap keyVal;   

    /** constructor **/
    public AssociateArray()
    {
        keyVal = new HashMap();        
    }    
    /** function to clear **/
    public void clear()
    {
        keyVal.clear();        
    }
    /** function to get size **/
    public int size()
    {
        return keyVal.size();
    }   
    /** function to insert element **/
    public void insert(String key, String val)
    {
        keyVal.put(key, val);        
    }    
    /** function to get element **/
    public String get(String ele)
    {
        return keyVal.get(ele);        
    }      
    /** function to remove element **/
    public void remove(String key)
    {
        keyVal.remove(key);              
    } 
    /** function to modify **/
    public void modify(String key, String val)
    {
        keyVal.put(key, val);        
    }        
}

/** Class AssociateArrayTest **/
public class AssociateArrayTest
{
    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in);
        System.out.println("Associate Array Test\n");   

        AssociateArray aa = new AssociateArray();

        char ch;
        /*  Perform Associate Array operations */
        do    
        {
            System.out.println("\nAssociate Array Operations\n");
            System.out.println("1. put ");
            System.out.println("2. get");
            System.out.println("3. remove");
            System.out.println("4. modify");
            System.out.println("5. clear");
            System.out.println("6. size");

            int choice = scan.nextInt();            
            switch (choice) 
            {
            case 1 : 
                System.out.println("Enter key and value");
                aa.insert(scan.next(), scan.next() );                     
                break;                          
            case 2 : 
                System.out.println("Enter element");
                String ele = scan.next();
                String str = aa.get(ele);
                if (str != null)
                    System.out.println("Result : "+ str);
                else
                    System.out.println("\nError : Not found\n");  
                break;        
            case 3 : 
                System.out.println("\nEnter key to be removed");
                aa.remove(scan.next() );
                break; 
            case 4 : 
                System.out.println("\nEnter key, value to be modified");
                aa.modify(scan.next(), scan.next() );  
                break;                                                        
            case 5 : 
                System.out.println("\nAssociate Array Cleared");
                aa.clear();
                break;    
            case 6 : 
                System.out.println("\nSize = "+ aa.size() );
                break;         
            default : 
                System.out.println("Wrong Entry \n ");
                break;   
            }    

            System.out.println("\nDo you want to continue (Type y or n) \n");
            ch = scan.next().charAt(0);                        
        } while (ch == 'Y'|| ch == 'y');            
    }
}


Output:

Associate Array Test


Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
fruit mango

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
vegetable tomato

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
drink water

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
drink
Result : water

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit
Result : mango

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
4

Enter key, value to be modified
fruit apple

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit
Result : apple

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
6

Size = 3

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
3

Enter key to be removed
fruit

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit

Error : Not found


Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
5

Associate Array Cleared

Do you want to continue (Type y or n)

y

Associate Array Operations

1. put
2. get
3. remove
4. modify
5. clear
6. size
6

Size = 0

Do you want to continue (Type y or n)

n



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