我需要帮助的是，我正在通过创建以下简单的销售计算器来学习Jave。我在此代码中有一个部分如下：
System.out.println ("Please make a selection:");
System.out.println ("1. Octopus Tentacles, 2. Rat Droppings");
System.out.println ("3. Sharks teeth, 4. Mountain Oysters");
System.out.println (" ");
// Since we don't have a primary database to pull from we use a dummy DB
while ( foodCount <= 1 )
{
System.out.print( "Enter selection (1 , 2, 3, 4): ");
result = input.nextInt();
if ( result == 1)
System.out.println( "You selected Octopus tentacles, price $4.99" );
else if ( result == 2)
System.out.println( "You selected Rat droppings, price $3.49" );
else if ( result == 3)
System.out.println( "You selected Sharks teeth, price $6.73" );
else if ( result == 4)
System.out.println( "You selected Mountain Oysters, price $9.95" );
break;
}
System.out.println (" ");
它允许我做出选择，我想要做的是将该值存储起来，以便在价格输入部分中使用。有谁可以帮助我吗？我是Java的新手，通过自己阅读互联网阅读书籍的方式学习，但在这种情况下找不到任何可以帮助我的东西。对此有任何帮助将不胜感激。
import java.io.*;
import java.text.*;
import java.util.*;
import java.util.Scanner;
import java.math.BigDecimal;
import java.text.NumberFormat;
class priceCalc {
public static void main (String[] args) throws IOException {
BufferedReader in = new BufferedReader (new InputStreamReader (System.in));
Scanner input = new Scanner(System.in);
int Quantity;
int result = 0;
int foodCount = 1;
double Price, Subtotal, SalesTax, TotalSale;
NumberFormat curForm = NumberFormat.getCurrencyInstance();
// Here is a simple display of available products
System.out.println (" ");
System.out.println ("Welcome to the IP2 part 2!");
System.out.println (" ");
System.out.println ("Please make a selection:");
System.out.println ("1. Octopus Tentacles, 2. Rat Droppings");
System.out.println ("3. Sharks teeth, 4. Mountain Oysters");
System.out.println (" ");
// Since we don't have a primary database to pull from we use a dummy DB
while ( foodCount <= 1 )
{
System.out.print( "Enter selection (1 , 2, 3, 4): ");
result = input.nextInt();
if ( result == 1)
System.out.println( "You selected Octopus tentacles, price $4.99" );
else if ( result == 2)
System.out.println( "You selected Rat droppings, price $3.49" );
else if ( result == 3)
System.out.println( "You selected Sharks teeth, price $6.73" );
else if ( result == 4)
System.out.println( "You selected Mountain Oysters, price $9.95" );
break;
}
System.out.println (" ");
// Create Scanner for input
Scanner key = new Scanner(System.in);
//Quantity
System.out.print ("Please enter quantity: ");
Quantity = key.nextInt();
System.out.println (" ");
//Price
System.out.print ("Please input price (price amount w/no $): ");
Price = key.nextDouble();
System.out.println (" ");
//Subtotal
Subtotal = Price * Quantity;
System.out.println ("Your subtotal is: " +curForm.format(Subtotal));
//Sales Tax
SalesTax = Subtotal * .065;
System.out.println ("Your sales tax is: " +curForm.format(SalesTax));
//Total Sale
TotalSale = Subtotal+SalesTax;
System.out.println ("Your total sale price is: " +curForm.format(TotalSale));
System.out.println (" ");
}
}
答案 0 :(得分：1)
我做了相关的修改并给出了理由。
class priceCalc {
public static void main (String[] args) throws IOException {
/*
You don't need a BufferedReader and also a Scanner, any one will do.
BufferedReader in = new BufferedReader (new InputStreamReader (System.in));
*/
Scanner input = new Scanner(System.in);
/*
Changed variable names to camelCase
http://en.wikipedia.org/wiki/Naming_convention_%28programming%29#Java
*/
int quantity;
int result = 0;
double price[] = new double[4];
double subTotal, salesTax, totalSale;
NumberFormat curForm = NumberFormat.getCurrencyInstance();
// Here is a simple display of available products
System.out.println (" ");
System.out.println ("Welcome to the IP2 part 2!");
System.out.println (" ");
System.out.println("Enter prices for each product");
System.out.println("Octopus tentacles: ");
price[0] = input.nextDouble();
System.out.println("Rat Droppings: ");
price[1] = input.nextDouble();
System.out.println("Sharks teeth: ");
price[2] = input.nextDouble();
System.out.println("Mountain Oysters: ");
price[3] = input.nextDouble();
System.out.println ("Please make a selection:");
System.out.println ("1. Octopus Tentacles, 2. Rat Droppings");
System.out.println ("3. Sharks teeth, 4. Mountain Oysters");
System.out.println (" ");
// Changed while into an infinite loop that will break on any input other than 1, 2, 3, and 4.
while (true)
{
System.out.print( "Enter selection (1 , 2, 3, 4): ");
result = input.nextInt();
if ( result == 1)
{
System.out.println( "You selected Octopus tentacles, "+price[0]);
subTotal = price[0]*getQuantity();
}
else if ( result == 2)
{
System.out.println( "You selected Rat droppings, "+price[1] );
subTotal = price[1]*getQuantity();
}
else if ( result == 3)
{
System.out.println( "You selected Sharks teeth, "+price[2] );
subTotal = price[2]*getQuantity();
}
else if ( result == 4)
{
System.out.println( "You selected Mountain Oysters, "+price[3] );
subTotal = price[3]*getQuantity();
}
else
{
break;
}
System.out.println ("Your subTotal is: " +curForm.format(subTotal));
salesTax = subTotal * .065;
System.out.println ("Your sales tax is: " +curForm.format(salesTax));
totalSale = subTotal+salesTax;
System.out.println ("Your total sale price is: " +curForm.format(totalSale));
System.out.println (" ");
}
System.out.println (" ");
/*
You don't need a second Scanner within the same scope
Scanner key = new Scanner(System.in);
*/
}
public static int getQuantity()
{
Scanner input = new Scanner(System.in);
System.out.println("Enter quantity: ");
int q = input.nextInt();
return q;
}
}
答案 1 :(得分：0)
通常情况下，我认为初学者错误是result的不正确范围 - 您可以在其中存储内容，但无法从父范围访问它。但是，此处result的范围是适当的。
你的例子看起来不完整，因为你试图循环（在foodCount <= 1上） - 但你总是在打破，所以你永远不会实际循环。因此，您应该只有一个选择 - result的值可以在以后的代码中使用，以便在您的计算中使用 - 就在Price，Subtotal，{{1}旁边}和SalesTax。 （遵循Java约定，这些变量名称都应以小写字母开头。）但是，在用户已选择具有相关价格的项目之后，我很困惑为什么要提示输入价格 - 除非这是你的我正试图纠正。
TotalSale以及其他变量才能生效。