Question

Create a currency converter java program. It will store conversion rates between some currency and the US$ for a month. The program flow is as follows:

(Part 1)Get user input for the historical data.

• Historical data will be the currency, day of the month (1-31) and conversion rate. Keep getting input until a null or space is entered for the currency.  
• Assume 3 currencies max will be entered.
• Store data in a 2-dimensional array. Maybe 32 rows by 5 columns matrix. Rows are day of month, columns are currency. Each cell will store the rate that was input for that Currency/Day of Month pair.
• Once 3 unique currencies are entered, do not accept any more unique currencies.

(Part 2) Get user input to lookup rates

• User will input a currency, day of the month and an amount.
• You will check if a rate exists for that currency & day. If it does you will multiply the amount by the rate and output the US$ equivalent. If the currency/date pair doesn't exist or there's no rate for it, output "Data Not Available"
• Keep requesting input until the user enters null or space for currency and then terminate the program

Example program output:

Enter Historical Data (Currency, Day of Month, Rate): EUR, 1, 1.11

Enter Historical Data (Currency, Day of Month, Rate): EUR, 2, 1.10

Enter Historical Data (Currency, Day of Month, Rate): JPY, 1, .0092

.....

Enter Historical Data (Currency, Day of Month, Rate): GBP, 31, 1.24

Enter Historical Data (Currency, Day of Month, Rate): [user enters null]

Enter Conversion Lookup(Currency, Day of Month, Amount): EUR, 1, 1000.00

1000.00 EUR = 1100.00 US$

Enter Conversion Lookup(Currency, Day of Month, Amount): GBP, 5, 2000.00

Data Not Available

Enter Conversion Lookup(Currency, Day of Month, Amount): GBP, 1, 1000.00

2000.00 GBP = 1300.00 US$

Enter Conversion Lookup(Currency, Day of Month, Amount): [user enters null]

program terminates

You can assume that days will be 1-31 but currencies and rates are dependent on user input.

Historical Data for exchange rates:

	EUR	GBP	MXN	JPY
1	1.10	1.30	18.59	109.80
2	1.10	1.29	18.65	110.00
3	1.09	1.28	18.76	109.73
4	1.09	1.29	18.76	109.73
5	Unavailable	Unavailable	Unavailable	Unavailable
6	1.09	1.29	18.70	109.77
7	1.09	1.29	18.67	109.79
8	1.09	1.30	18.63	110.08
9	1.08	1.31	18.60	109.82
10	1.08	1.30	18.54	109.77
11	1.08	1.30	18.54	109.80
12	Unavailable	Unavailable	Unavailable	Unavailable
13	1,08	1.30	18.56	109.85
14	1.08	1.30	18.59	109.86
15	1.08	1.29	18.57	111.25
16	1.08	1.29	18.84	112.06
17	1.08	1.30	18.91	111.58
18	1,08	1.,30	18.91	111.58
19	Unavailable	Unavailable	Unavailable	Unavailable
20	1.09	1.29	19.08	110.67
21	1.09	1.30	19.09	110.21
22	1.09	1.29	19.29	110.41
23	1.10	1.29	19.50	109.53
24	1.10	1.28	19.62	108.12
25	1.10	1.28	19.62	108.12
26	Unavailable	Unavailable	Unavailable	Unavailable
27	1.11	1.28	19.40	108.31
28	1.12	1.28	19.46	107.16
29	1.11	1.29	19.52	107.56
30	1.12	1.30	19.86	106.15
31	1.12	1.30	20.05	106.26

Answer 1

package HomeworkLib;

import java.util.Arrays;
import java.util.Scanner;

public class CurrencyConverter {
    protected static String[][] data =new String[32][4];
    public static void main(String[] args){

        System.out.println("Get Historical Data");
        initializeTable();
        loadHistoricalData();

        //System.out.println("Currency Loopup");
        currencyLookup();

        for(int i=0;i<data.length;i++)
            System.out.println(Arrays.toString(data[i]));
    }

    private static void initializeTable() {
        for(int i=1;i<data.length;i++){
            data[i][0] =Integer.toString(i);
            for(int j=1;j<data[0].length;j++){
                data[i][j]="Unavailable";
            }
        }
    }

    private static void currencyLookup() {
        String line,currency;
        String[] row=null;
        int day;
        boolean isCurrencyFound =false;
        double amount,convertedAmount;
        Scanner scanner =new Scanner(System.in);
        System.out.println("Enter Currency Loopup Data (Currency, Date of Month, Amount): ");
        line =scanner.next();

        while (true){
            convertedAmount=0; isCurrencyFound=false;
            row =line.split(",", -1);
            currency=row[0];
            day=Integer.parseInt(row[1]);
            amount=Double.parseDouble(row[2]);
            if(currency ==null || currency.trim() =="" || currency.trim().length()==0){
                break;
            }

            //Calculate the Amount
            int i;
            for(i=1;i<data[0].length;i++){
                if(data[0][i].equalsIgnoreCase(currency)){
                    isCurrencyFound=true;
                    if(("Unavailable").equalsIgnoreCase(data[day][i])){
                        System.out.println("Data not available");
                        break;
                    }
                    convertedAmount=amount * Double.parseDouble(data[day][i]);

                    break;
                }
            }
            if(isCurrencyFound)
                System.out.println(amount +currency+"="+convertedAmount);
            else
                System.out.println("Allowed Curency:"+Arrays.toString(data[0]));
            System.out.println("Enter Currency Loopup Data (Currency, Date of Month, Amount): ");
            line =scanner.next();
        }
    }

    private static void loadHistoricalData() {
        String line=null,rate,currency;
        boolean isCurrencyAllowed=false;
        int day;
        String[] row;
        Scanner scanner =new Scanner(System.in);
        System.out.println("Enter Historial Data (Currency, Date of Month, Rate): ");
        line =scanner.next();
        while(true){
            isCurrencyAllowed=false;
            row =line.split(",", -1);
            currency=row[0];
            day=Integer.parseInt(row[1]);
            rate=row[2];
            if(currency ==null || currency.trim() =="" || currency.trim().length()==0){
                break;
            }
            for(int i=1;i<data[0].length;i++){
                if(data[0][i] =="" || data[0][i] ==null){
                    data[0][i] =currency;
                    data[day][i]=rate;
                    isCurrencyAllowed=true;
                    break;
                }
                if(currency.equalsIgnoreCase(data[0][i])){
                    data[day][i] =rate;
                    isCurrencyAllowed=true;
                    break;
                }
            }
            if (!isCurrencyAllowed) System.out.println("Only 3 Currency Allowed:"+Arrays.toString(data[0]));
            System.out.println("Enter Historial Data (Currency, Date of Month, Rate): ");
            line =scanner.next();
        }
        System.out.println("Data Loading Done");
    }
}