Question

我正在为学校作业，并且已经有一个基本程序，可以通过询问总里程，汽车的平均 mpg 和每加仑汽油的成本来计算旅行的总成本。这很有效，但是我还需要添加更多项目，并且我不确定如何执行。首先，我需要包含某种菜单，以提供答案来计算旅行总费用或退出程序。接下来，我需要在程序中的某个位置添加一个油

import java.util.Scanner;
public class GasCalculator {
    public static void main (String args[])
    {
        Scanner scan = new Scanner(System.in);
        System.out.println("How many miles do you plan to travel?");
        int miles = scan.nextInt();
        System.out.println("So you will drive " + miles +" miles.");
        System.out.println("What is the price of gas?");
        double gas = scan.nextDouble();
        System.out.println("Ok, so gas costs $" + gas +" per gallon.");
        System.out.println("What is the average MPG of your car? Use the nearest whole number.");
        int mpg = scan.nextInt();
        System.out.println("So, you get " + mpg +" miles per gallon.");
        System.out.println("Would you like an oil change? Enter Y or N");
        double cost = (miles / mpg * gas + oil);
        System.out.println("Below is your total cost");
        System.out.println(String.format("Your trip will cost $" + cost + "."));
    }
}

如您所见，我添加了一点询问他们是否要换油。我这样做的愿景是为 y 或 n 答案创建一个变量，然后根据 y 或 n 创建一个 if else 语句。如果 y，它将为新变量“oil”添加 39.99。如果 n，它将使变量为 0。油已被合并到最终方程式中，无论其价值如何。

我不是在寻找任何人为我做我的任务。我想我想看看这是什么样子，或者如果有人有任何输入，我应该如何解决这个问题。

2

1

0

Answer 1

首先，我需要包含某种菜单，可以选择计算旅行费用或退出程序。

可以使用switch语句。

//ask for user to enter 0 to exit, 1 to calculate the trip
switch(answer) {
     case 0 : System.exit(0);
              break;
     case 1 : //calculate cost trip here
              break;
     default : System.exit(0);
}

接下来，我需要在程序中的某个地方加入一点，询问用户是否想要换油，然后根据答案将其添加到总数中

那么你可以得到用户的值与你的Scanner对象像你一样，写一个 if 语句来检查这个值。

System.out.println("Would you like an oil change? Enter Y or N");
//here get the value of the user using your scanner object
double oil = 0;
if(/*test if value is equals to y*/)
    oil += 39.99;

为了避免测试值是否为"y"或"Y"，请使用String类的方法equalsIgnoreCase。

当这将工作时，您可以将计算行程成本的功能包装在一个方法中，并在 switch 语句的情况 1 中调用此方法。

Answer 2

Edit

import java.util.Scanner;
public class GasCalculator {
    public static void main (String args[])
    {
        double total = 0;       
        Scanner scan = new Scanner(System.in);
        System.out.println("How many miles do you plan to travel?");
        int miles = scan.nextInt();
        System.out.println("So you will drive " + miles +" miles.");
        System.out.println("What is the price of gas?");
        double gas = scan.nextDouble();
        System.out.println("Ok, so gas costs $" + gas +" per gallon.");
        System.out.println("What is the average MPG of your car? Use the nearest whole number.");
        int mpg = scan.nextInt();
        System.out.println("So, you get " + mpg +" miles per gallon.");
        System.out.println("Would you like an oil change? Enter Y or N");
        char oil = scan.next().charAt(0);
        if (Character.toUpperCase(oil) == 'Y'){
            System.out.println("Cost of oil change id 39.99);
            System.out.println("39.99 will be added to your total cost");
            total += 39.99;
        }
        double cost = (miles / mpg * gas);
        total += cost;
        String menu = "Pick a menu option: \n"
                      + "1. Calculate total \n"
                      + "2. exit";
        System.out.println(menu);
        int choice = scan.nextInt();
        if (choice == 1){
            System.out.println("Below is your total cost");
            System.out.println(String.format("Your trip will cost $" + total + "."));
        } else {
            System.exit(0);
        }
    }
}

Answer 3

您可以实现这样的退出选项：

System.out.println("Choose your desired option:\n1)Calculate Trip Cost\n2)Exit");
int answer = scan.nextInt();
if (answer==1){
    // the rest of your program
    System.out.println("How many miles do you plan to travel?");
    int miles = scan.nextInt();
    System.out.println("So you will drive " + miles +" miles.");
    System.out.println("What is the price of gas?");
    double gas = scan.nextDouble();
    System.out.println("Ok, so gas costs $" + gas +" per gallon.");
    System.out.println("What is the average MPG of your car? Use the nearest whole number.");
    int mpg = scan.nextInt();
    System.out.println("So, you get " + mpg +" miles per gallon.");
    System.out.println("Would you like an oil change? Enter Y or N");
    double cost = (miles / mpg * gas + oil);
    System.out.println("Below is your total cost");
    System.out.println(String.format("Your trip will cost $" + cost + "."));
}