datatypes and arrays in java - arrays

Question

Thoroughly confused on how to do this. What I want to do is to place the city with the lowest min, or max in the output. My understanding is you cannot throw a string in with another datatype in a method. How in the world can I match the name with the lowest temperature?
Lets say I want 3 cities:
I want to make the array 3 then:
Then I will add in the following cities, (Alanta, New York, Richmond)
The cities temperatures are (42.2, 98.8, -12.4)
Min is -12.4
Max is 98.8
That I have, how do I link Richmond's String that is stored in array[2] to temperature's double that is stored in array[2]? Any help is much appreciated.
import javax.swing.JOptionPane;
import java.util.Scanner;
import java.lang.Math;
public class Ex9
{
public static void main(String[] args)
{
String message ="";
double min = 0, max = 0, avg = 0;
int counter = 1;
int numberOfCities = Integer.parseInt(JOptionPane.showInputDialog(null, "How many cities would you like to enter?"));
String[] nameOfCities = new String[numberOfCities];
double[] temperatureOfCities = new double[numberOfCities];
for (int i = 0; i < nameOfCities.length; i++)
{
nameOfCities[i] = JOptionPane.showInputDialog(null, "Please enter the name of city " +counter+" :");
temperatureOfCities[i] = Double.parseDouble(JOptionPane.showInputDialog(null, "Please enter the current temperature of the city " + counter +" :"));
message += "City name " + nameOfCities[i] + ".\n"
+ "Temperature of city " + temperatureOfCities[i] + " is degrees\n";
counter++;
}//end numberOfCities loop
if(
JOptionPane.showMessageDialog(null, message + "\nThe average temperature is " +findAvg(temperatureOfCities)+ "\n[Name of city] has the lowest temperature, which is " + findMin(temperatureOfCities) + "\n[Name of city] has the highest temperature, which is " + findMax(temperatureOfCities));
}//end main
public static double findAvg(double[] temperatureOfCities)
{
double sum =0;
for(int i=0;i<temperatureOfCities.length;i++)
{
sum += temperatureOfCities[i];
}
sum = sum/temperatureOfCities.length;
return sum;
}//end findAvg
public static double findMin(double[] temperatureOfCities)
{
double min=0;
for(int i =0; i <temperatureOfCities.length;i++)
{
if (temperatureOfCities[i] <= temperatureOfCities[0])
{
min = temperatureOfCities[i];
}
}//end for loop
return min;
}//end findMin
public static double findMax(double[] temperatureOfCities)
{
double max=0;
for(int i =0; i <temperatureOfCities.length;i++)
{
if (temperatureOfCities[i] >= temperatureOfCities[0])
{
max = temperatureOfCities[i];
}
}//end for loop
return max;
}//end findMax
}//end program

Answer 1

Two main approaches here:
1) The procedural approach - just pass both arrays around instead of just one array. If they're kept synchronized there's no problem - just use the same index for both.
2) The object oriented approach - Define a class TemperatureReading with double temperature and string cityName. Then you can make a TemperatureReading[] array and pass it around, and the data is naturally associated.

Answer 2

Change your findMin, findAvg, and findMax methods to return a composite Measurement object.
class Measurement {
final double temperature;
final String cityName;
Measurment(String cityName, double temperature)
{
this.temperature = temperature;
this.cityName = cityName;
}
}
The updated methods could look something like this:
public static Measurement findMax(String[] nameOfCities, double[] temperatureOfCities) {
double maxTemp=0;
String maxName=null;
for(int i =0; i <temperatureOfCities.length;i++)
{
if (temperatureOfCities[i] >= temperatureOfCities[0])
{
maxTemp = temperatureOfCities[i];
maxName = nameOfCities[i];
}
} //end for loop
return new Measurement(maxTemp, maxName);
}
Now you can use the results like this:
Measurement maxMeasurement = findMax(nameOfCities, temperatureOfCities);
System.out.println(maxMeasurement.cityName + "has a temperature of " + maxMeasurement.temperature);
Similar goes for findMin and findAvg.