Thread: Help: Insert , Delate, Display in my project

Someone who can help to improve my program .. I need to add an Insert, Display and Delete in my program
but i dont know how to do that.
the sample output just like this :

-~-~-~-CONVERSION CHOICES-~-~-~-
+-------------------------------+
| [1] - Decimal |
| [2] - Binary |
| [3] - Octal |
| [4] - Hexadecimal |
| [5] - Exit |
+-------------------------------+

Select Number: 1
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
+-------------------------------+
| [1] - ADD |
| [2] - DELETE |
| [3] - DISPLAY |
| [4] - Back to Choices |
| [5] - Back to Main Menu |
+-------------------------------+
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
Enter your choice: 1
Enter Code: 1
Enter a Decimal Number: 200
Successfully added!

-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
+-------------------------------+
| [1] - ADD |
| [2] - DELETE |
| [3] - DISPLAY |
| [4] - Back to Choices |
| [5] - Back to Main Menu |
+-------------------------------+
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
Enter your choice: 1
Enter Code: 2
Enter a Decimal Number: 100
Successfully added!

-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
+-------------------------------+
| [1] - ADD |
| [2] - DELETE |
| [3] - DISPLAY |
| [4] - Back to Choices |
| [5] - Back to Main Menu |
+-------------------------------+
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
Enter your choice: 3
1.The Binary equivalent of 200 is : 11001000
The Octal equivalent of 200 is : 310
The Hex equivalent of 200 is : C8
2.The Binary equivalent of 100 is : 1100100
The Octal equivalent of 100 is : 144
The Hex equivalent of 100 is : 64

-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
+-------------------------------+
| [1] - ADD |
| [2] - DELETE |
| [3] - DISPLAY |
| [4] - Back to Choices |
| [5] - Back to Main Menu |
+-------------------------------+
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
Enter your choice: 2
Enter Code: 1
Successfully Deleted!

-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
+-------------------------------+
| [1] - ADD |
| [2] - DELETE |
| [3] - DISPLAY |
| [4] - Back to Choices |
| [5] - Back to Main Menu |
+-------------------------------+
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
Enter your choice: 3
1.The Binary equivalent of 100 is : 1100100
The Octal equivalent of 100 is : 144
The Hex equivalent of 100 is : 64

Here is my sample code so far.
MainProgram.java

import java.util.Scanner;
public class MainProgram {
 
    public static int menu()
    {
        Scanner in = new Scanner (System.in);
 
        int ans = 0;
 
        System.out.println("\t\t-~-~-~-CONVERSION CHOICES-~-~-~-");
        System.out.println("\t\t+-------------------------------+");
        System.out.println("\t\t|       [1] - Decimal           |");
        System.out.println("\t\t|       [2] - Binary            |");
        System.out.println("\t\t|       [3] - Octal             |");
        System.out.println("\t\t|       [4] - Hexadecimal       |");
        System.out.println("\t\t|       [5] - Exit              |");
        System.out.println("\t\t+-------------------------------+");
        System.out.println("\t\t-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-");
        System.out.print("Select a Number: ");
        ans = in.nextInt();
 
        while (ans<=0 || ans >5)
        {
            System.out.println("\t\tINVALID INPUT");
            System.out.println();
            System.out.print("Enter Again: ");
            ans = in.nextInt();
        }
 
        return ans;
 
    }
    public static void main(String [] args) 
    {
        Scanner in = new Scanner (System.in);
 
        int ans = menu();
 
        while(true)
        {
            switch(ans)
            {
                case 1:
                    int anscon1 ;
                        System.out.println();
                        System.out.println("\t\t-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-");
                        System.out.println("\t\t+-------------------------------+");
                        System.out.println("\t\t|   [1] - ADD                   |");
                        System.out.println("\t\t|   [2] - DELETE                |");
                        System.out.println("\t\t|   [3] - DISPLAY               |");
                        System.out.println("\t\t|   [4] - Back to Choices       |");
                        System.out.println("\t\t|   [5] - Back to Main Menu     |");
                        System.out.println("\t\t+-------------------------------+");
                        System.out.println("\t\t-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-");
                        System.out.print("Enter your choice:  ");
                        anscon1 = in.nextInt();
 
                        if(anscon1 == 1)
                        {
 
                        }
                        if(anscon1 == 2)
                        {
 
                        }
                        if(anscon1 == 3)
                        {
 
                        }
                        if(anscon1 == 4)
                        {
                            System.out.println("\t\t   -o-o-o-Choices-o-o-o-");
                        }
                        if(anscon1 == 5)
                        {
                            ans = menu();
                        }
                    break;

Conversion.java

import java.util.Scanner;
 
public class Conversion {
 
    /*---------------------DECIMAL---------------------*/
 
    // Decimal to Binary
    public String DecToBin()
    {
        Scanner in = new Scanner (System.in);
        String numDec = " ";
        System.out.print("Enter a Decimal Number: ");
        numDec = in.nextLine();
        int binDec = Integer.parseInt(numDec,10);
        String decBin = Integer.toBinaryString(binDec);
        System.out.println("The Binary equivalent is: " + decBin);
        System.out.println("-------------------------------------");
        return decBin;
    }
 
    //Decimal to Octal
    public String DecToOct()
    {
        Scanner in = new Scanner (System.in);
        String numDec = " ";
        System.out.print("Enter a Decimal Number: ");
        numDec = in.nextLine();
        int octDec = Integer.parseInt(numDec,10);
        String decOct = Integer.toOctalString(octDec);
        System.out.println("The Octal equivalent is: " + decOct);
        System.out.println("-------------------------------------");
        return decOct;
    }
 
    //Decimal to Hexadecimal
    public String DecToHex()
    {
        Scanner in = new Scanner (System.in);
        String numDec = " ";
        System.out.print("Enter a Decimal Number: ");
        numDec = in.nextLine();
        int hexDec = Integer.parseInt(numDec,10);
        String decHex = Integer.toHexString(hexDec);
        System.out.println("The Octal equivalent is: " + decHex.toUpperCase());
        System.out.println("-------------------------------------");
        return decHex;
    }
 
}

The first question I'd ask is, "To what are you adding the user's input?" The answer should be, "To some kind of collection of objects that describe each data item." Your program doesn't have the data item class or the collection in which to store objects of that class, so you need to add them. The data object might be a String stored in an ArrayList<String> at the index specified by the "Code", or you could create your own class to store the data value, Code, and any/all of the conversions.

The conversion methods you've shown are doing too much. Based on the sample run you've shown, the user enters one data value, not an Integer or a Decimal, or a ?. So your program should accept the data value in a common format in one place, store it, and then calculate the conversions on that value. This approach should require only one Scanner object for the whole program, not the several you are currently creating.

I see you're new at using methods, not quite sure what a method should do, when to use a new one, etc. A general rule of thumb is that a method should do exactly one thing, do it very well, and the one thing the method does should be described by the method's name.

Refactor your program some and come back when you're ready to move forward. Good luck, and keep coding!