电费/能源账单计算器：Java

Question

我无法弄清楚这个用于计算计算机能源成本的小型电力/能源计算器到底出了什么问题。

我将不胜感激。

计划：

import java.util.Scanner;

public class ElectricityCalculations {
   public static void main (String [] args) {
      Scanner scnr = new Scanner(System.in);
      double usageHoursPerDay      = 0; // Hours computer is on per day
      double usageDaysPerWeek      = 0; // Days computer is used per week
      double usageWeeksPerYear     = 0; // Weeks computer is used per year
      double wattsPerHour          = 0; // Watts used by computer per hour
      final double COST_PER_KWH    = 0.145; // Prices of power per kilowatt hour
      final double LBS_CO2_PER_KWH = 0.58815; // Pounds of CO2 generated per KWH
      double usageHoursPerYear     = 0; // Amount of hours on per year
      double usageWattHoursPerYear = 0; // Amount of watt hours consumed per year
      double usageKWHPerYear       = 0; // Amount of KWH used in a year
      double costPerYear           = 0; // Total cost per year
      double lbsCO2PerYear         = 0; // Total amount of CO2 in pounds released per year

      // Input Values
      System.out.println("How many hours is your computer on per day?");
      usageHoursPerDay  = scnr.nextDouble();
      System.out.println("How many days per week is your computer used?");
      usageDaysPerWeek  = scnr.nextDouble();
      System.out.println("How many weeks per year is your computer used?");
      usageWeeksPerYear = scnr.nextDouble();
      System.out.println("How many watts per hour does your computer use? (Suggestive value for desktop: 100, laptop: 30).");
      wattsPerHour      = scnr.nextDouble();

      // Calculations
      usageHoursPerYear     = usageHoursPerDay * 365;
      usageWattHoursPerYear = wattsPerHour * 8760; // 8760 is the number of hours in a year
      usageKWHPerYear       = usageWattHoursPerYear / 1000;
      costPerYear           = usageKWHPerYear * COST_PER_KWH;
      lbsCO2PerYear         = LBS_CO2_PER_KWH * usageKWHPerYear;

      // Printing Energy Audits
      System.out.println("Computer Energy Audit");
      System.out.println("You use your computer for " + usageHoursPerYear + " hours per year.");
      System.out.println("It will use " + usageWattHoursPerYear + " KWH/year.");
      System.out.println("Whih will cost " + costPerYear + "$/year for electricity.");
      System.out.println("Generating that electricity will produce " + lbsCO2PerYear + " lbs of CO2 pollution.");

      return;
   }
}

输入：

8 小时/天

5 天/周

50 周/年

100 瓦/小时

我的（错误输出）：

计算机能源审计：

您每年使用计算机的时间为 2920.0 小时。

它将使用 876000.0 KWH/年。

电费为 127.02 美元/年。

发电将产生 515.2194 磅的二氧化碳污染。

正确的输出：

计算机能源审计：

您每年使用计算机的时间为 2000.0 小时。

它将使用 200.0 KWH/年。

这将花费 28.999999999999996 美元/年的电费。

发电将产生 117.63 磅的二氧化碳污染。

Answer 1

您输入了每周的天数和每年的周数，但忘记在计算中使用它们。此外，您不是打印 KWH，而是显示存储瓦特小时的变量。

// Calculations
usageHoursPerYear     = usageHoursPerDay * usageDaysPerWeek * usageWeeksPerYear; //calculate based on time used, not 365 days in the year
usageWattHoursPerYear = wattsPerHour * usageHoursPerYear; //use variable from above line
usageKWHPerYear       = usageWattHoursPerYear / 1000;
costPerYear           = usageKWHPerYear * COST_PER_KWH;
lbsCO2PerYear         = LBS_CO2_PER_KWH * usageKWHPerYear;

// Printing Energy Audits
System.out.println("Computer Energy Audit");
System.out.println("You use your computer for " + usageHoursPerYear + " hours per year.");
System.out.println("It will use " + usageKWHPerYear + " KWH/year."); //changed to correct variable
System.out.println("Whih will cost " + costPerYear + "$/year for electricity.");
System.out.println("Generating that electricity will produce " + lbsCO2PerYear + " lbs of CO2 pollution.");