AerospaceCalculator

package calculator;

import java.util.Scanner;

public class AerospaceCalculator {

	static String height;
	static String temperature;
	static String pressure;
	static String density;
	static String whatToFind;

	public static void main(String[] args) {

		Scanner reader = new Scanner(System.in);

		System.out.println("Thanks for using Andrew's Aerospace Calculator Version 2.0");

		System.out.println("For the following inputs, either give a number or put 'unknown'");
		System.out.println("Also, please round decimals to the nearest hundredth or add zeros so that you have hundredths.");

		System.out.println("What is the height in meters?");
		height = reader.next();

		System.out.println("What is the temperature in degrees celsius?");
		temperature = reader.next();

		System.out.println("What is the pressure in kPa?");
		pressure = reader.next();

		System.out.println("What is the density in kg/m^3?");
		density = reader.next();

		System.out.println("What would you like to find? (Enter a number)");
		System.out.println("1) Temperature");
		System.out.println("2) Pressure");
		System.out.println("3) Density");
		whatToFind = reader.next();

		switch(whatToFind) {

		case "1":
			System.out.println("Calculating Temperature...");
			findTemp();
			System.out.println("Temperature is: " + temperature);
			break;
		case "2":
			System.out.println("Calculating Pressure...");
			findPressure();
			System.out.println("Pressure is: " + pressure);
			break;
		case "3":
			System.out.println("Calculating Density...");
			findDensity();
			System.out.println("Density is: " + density);
			break;
		default:
			System.out.println("That input was not a number or wasn't recognized. Please try again.");
			break;

		}



	}

	public static void findTemp() {

		if(height == "unknown"){
			System.out.println("You cannot find temperature without height.");
		} else {
			double temp = Double.parseDouble(height);
			double hite = Double.parseDouble(temperature);
			temp = 15.04 - (0.00649 * hite);
			temperature = Double.toString(hite);
		}

	}

	public static void findPressure() {

		if(temperature == "unknown"){
			findTemp();
		} else {
			double press = Double.parseDouble(pressure);
			double temp = Double.parseDouble(temperature);
			press = 101.29 * (Math.pow((temp + 273.1) / (288.08), 5.256));
			pressure = Double.toString(press);
		}

	}

	public static void findDensity() {

		if(pressure == "unknown") {
			findPressure();
		} else {
			double dens = Double.parseDouble(density);
			double press = Double.parseDouble(pressure);
			double temp = Double.parseDouble(temperature);
			dens = press / (0.2869 * (temp + 273.1));
			density = Double.toString(dens);
		}

	}

}