将值从一种方法返回到另一种方法以在输出中使用

Question

我不知道如何 return 将 finalCost 的值传给 main 方法并打印它。

import java.util.*;

public class PhonePlan {
    private static double basecost = 8.5;
    private static double rate = 0.35;
    private static double discount = 0.15;

    public static void main(String[] args) {
        //Scan input for downloadLimit
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter the download limit in GB: ");
        int downloadLimit = scan.nextInt();
        // Call other method
        calcMonthlyCharge(downloadLimit);

        System.out.println("Plan monthly cost: " + calcMonthlyCharge(finalCost));
    }

    public static double calcMonthlyCharge(double downloadLimit) {
        // Calculate final cost
        double fullCost = downloadLimit * rate + basecost;
        double planDiscount = fullCost * discount;
        double finalCost = fullCost - planDiscount;
        return finalCost;
    }
}

具体来说，我找不到如何在“println”行中使用 returned 值。

    System.out.println("Plan monthly cost: " + calcMonthlyCharge(finalCost) ); 
} 
public static double calcMonthlyCharge(double downloadLimit) { 
    // Calculate final cost 
    double fullCost = downloadLimit * rate + basecost; 
    double planDiscount = fullCost * discount; 
    double finalCost = fullCost - planDiscount; 
    return finalCost;
}

Answer 1

您调用 calcMonthlyCharge(downloadLimit)，但不存储返回值。

当你打电话给System.out.println("Plan monthly cost: " + calcMonthlyCharge(finalCost) ); finalcost 是什么未知，这是一个只存在于 calcMonthlyCharge

范围内的变量

要么存储 calcMonthlyCharge(downloadLimit) 的返回值并重用该值进行打印，要么在 println 中使用 calcMonthlyCharge(downloadLimit) 并使用 downloadLimit 作为参数来获取新的返回值。

将值从一种方法返回到另一种方法以在输出中使用

Returning a value from one method to another to be used in the output

java

printing

methods

return