The content of the if statements is not relevant to my question and I've removed as much as I can that's irrelevant.

I'm really struggling to understand what I need to do to have the method getNetSalary return the value of the netSalary variable.

I think I need to instantiate an object to have a value to be "returnable" but no matter how many youtube videos and other forum posts I read I can't get my head around it.

package mortgage;

import java.util.Scanner;

public class MortgageDecision {

    public static void main(String[] args) {
        double grossSalary;
        Scanner input = new Scanner(System.in);
        System.out.print("Gross Annual Salary: £");
        grossSalary = input.nextDouble();
    }

    public static double getNetSalary(double grossSalary) {
        
        double netSalary;
        double taxFreeAllowance = 12500;
        double taxFreeDeduction = 0;
        double tax = 0;

        if (grossSalary > 100000) {
            taxFreeDeduction = (grossSalary - 100000) / 2;
        }

        if (taxFreeDeduction > 12500) {
            taxFreeDeduction = 12500;
        }

        taxFreeAllowance = taxFreeAllowance - taxFreeDeduction;

        if (grossSalary <= 50000) {
            tax = (grossSalary - taxFreeAllowance) * 0.2;
        } else if (grossSalary <= 100000) {
            tax = ((grossSalary - 50000) * 0.3)
                      ((grossSalary - taxFreeAllowance
                    - (grossSalary - 50000)) * 0.2);
        } else if (grossSalary > 100000) {
            tax = ((grossSalary - 100000) * 0.4)   15000
                      ((50000 - taxFreeAllowance) * 0.2);
        }

        if (tax < 0) {
            tax = 0;
        }

        netSalary = grossSalary - tax;
         
        return netSalary;
    }

CodePudding user response：

You want to call you getNetSalary method in your main method like so:

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.print("Gross Annual Salary: £");
    double grossSalary = input.nextDouble();
    System.out.println(String.valueOf(grossSalary);
    double netSalary = getNetSalary(grossSalary);
    System.out.print("Net salary: £");
    System.out.println(String.valueOf(netSalary);
}

And some hints on programm structure in Java:

• You seem to use a C/C stlye of programming, usually in Java you don't need to declaration all used variables at the top.
• That is why I would inline netSalary and move down the declaration of tax
• You declared taxFreeAllowance inside the method and you don't overwrite it inside. You might want to extract it as a constant static field.