Question

JAVA:

Using the forex.csv

Given a file with the USD to conversion rate Convert X amount of Currency A to Currency B User inputs are the source and destination currency symbols and the amount. $3000 AUD = $42,641.40 MXN

Symbol	Currency	Dollar
USD	US Dollar	1
EUR	Euro	0.842850125
GBP	British Pound	0.761549464
INR	Indian Rupee	63.72054347
AUD	Australian Dollar	1.259237335
CAD	Canadian Dollar	1.257801755
SGD	Singapore Dollar	1.359074339
CHF	Swiss Franc	0.970036942
MYR	Malaysian Ringgit	4.280492421
JPY	Japanese Yen	110.115807
CNY	Chinese Yuan Renminbi	6.7191876
NZD	New Zealand Dollar	1.344839521
THB	Thai Baht	33.26460563
HUF	Hungarian Forint	255.9880337
AED	Emirati Dirham	3.672967434
HKD	Hong Kong Dollar	7.818109862
MXN	Mexican Peso	17.87416927
ZAR	South African Rand	13.40320648
PHP	Philippine Peso	50.3272521
SEK	Swedish Krona	8.106236601
IDR	Indonesian Rupiah	13332.07455
SAR	Saudi Arabian Riyal	3.750330177
BRL	Brazilian Real	3.119954853
TRY	Turkish Lira	3.535513983
KES	Kenyan Shilling	103.8403002
KRW	South Korean Won	1128.191103
EGP	Egyptian Pound	17.7925951

Answer 1

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class CurrencyConverter {
  
private static final String FILENAME = "forex.csv";
  
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
Scanner fileReader;
ArrayList<String> symbols = new ArrayList<>();
ArrayList<Double> rates = new ArrayList<>();
  
// read the file "forex.csv" and populate the 2 lists
// data in the input are separated by comma (Eg: USD,US Dollar,1)
try
{
int count = 0; // counter variable for how many records are being read from the input file
fileReader = new Scanner(new File(FILENAME));
while(fileReader.hasNextLine())
{
String line = fileReader.nextLine().trim();
String[] data = line.split(",");
String symbol = data[0];
// data[1] is the currency and it is of no use to us, so ignore it
double rate = Double.parseDouble(data[2]);
  
symbols.add(symbol);
rates.add(rate);
count++;
}
fileReader.close();
System.out.println(count + " records are read from file: " + FILENAME);
}catch(FileNotFoundException fnfe){
System.out.println(FILENAME + " could not be found!");
System.exit(-1);
}
  
// user input for source and destination currency and the amount
System.out.print("\nEnter the source currency symbol(Eg: USD): ");
String inpSourceSymbol = sc.nextLine().toUpperCase().trim();
System.out.print("Enter the destination currency symbol(Eg: CAD): ");
String inpDestSymbol = sc.nextLine().toUpperCase().trim();
System.out.print("Enter the amount: $");
String inp = sc.nextLine().trim();
while(!isDouble(inp))
{
System.out.println("Please enter a valid double value for amount!");
System.out.print("Enter the amount: $");
inp = sc.nextLine().trim();
}
double amount = Double.parseDouble(inp);
  
double convAmt = getConvertedAmount(symbols, rates, inpSourceSymbol, inpDestSymbol, amount);
  
System.out.println("\n$" + amount + " " + inpSourceSymbol + " = $"
+ String.format("%.2f", convAmt) + " " + inpDestSymbol);
}
  
private static double getConvertedAmount(ArrayList<String> symbols, ArrayList<Double> rates,
String source, String dest, double amt)
{
double res = 0.0, sourceRate, destRate = 0.0;
boolean found = false;
int index = -1;
  
// find the source symbol in the symbols list
for(int i = 0; i < symbols.size(); i++)
{
if(symbols.get(i).equals(source))
{
found = true;
index = i;
break;
}
}
  
// source symbol is present
if(found)
{
// get the source rate
sourceRate = rates.get(index);
amt /= sourceRate;
  
// find the index of destinaton symbol
for(int i = 0; i < symbols.size(); i++)
{
if(symbols.get(i).equals(dest))
{
// destination symbol present, so get the destination rate
destRate = rates.get(i);
break;
}
}
  
res = (amt * destRate);
}
return res;
}
  
private static boolean isDouble(String s)
{
try
{
Double.parseDouble(s);
return true;
}catch(NumberFormatException nfe){
return false;
}
}
}

****************************************************************** SCREENSHOT *********************************************************

run: 27 records are read from file: forex.csv Enter the source currency symbol (Eg: USD): AUD Enter the destination currency symbol (Eg: CAD) : MXN Enter the amount: $3000 $3000.0 AUD = $42583.32 MXN BUILD SUCCESSFUL (total time: 18 seconds)