尝试为我的编程类介绍做这个程序。我无法让它运行,甚至在我添加了printwriter之前它没有错误仍然无法运行。任何提示将不胜感激(如何解决它以及如何让打印机工作。
package pa2;
import java.io.PrintWriter;
import java.util.Scanner;
public class pa2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
}
{
Scanner keyboard = new Scanner(System.in);
PrintWriter prw = new PrintWriter ("pa2output.txt");
// variables
double tshirt, chips, coke, tax, sale, subtotal, total, tshirtcost, chipscost, cokecost, deposit, cokewdeposit, discount, change, payment, numshirt, numcoke, numchips;
String name;
tshirt = 18.95;
chips = 1.79;
coke = 2.99;
deposit = 1.2;
tax = .06;
sale = .15;
// menu
System.out.print("What is your name? ");
prw.print("What is your name? ");
name = keyboard.nextLine();
System.out.println("Welcome to Denny's " + name + "! " + "We have the following items for sale:");
prw.print("Welcome to Denny's " + name + "! " + "We have the following items for sale:");
System.out.println("T-shirt $" + tshirt + "15% off");
prw.print("T-shirt $" + tshirt + "15% off");
System.out.println("Chips $" + chips + "15% off");
prw.print("Chips $" + chips + "15% off");
System.out.println("Coke $" + coke);
prw.print("Coke $" + coke);
// input
System.out.println("How many T-shirts do you want?");
prw.print("How many T-shirts do you want?");
numshirt = keyboard.nextDouble();
System.out.println("How many bags of patato chips?");
prw.print("How many bags of patato chips?");
numchips = keyboard.nextDouble();
System.out.println("What about 12-pack Coke?");
prw.print("What about 12-pack Coke?");
numcoke = keyboard.nextDouble();
System.out.println("Please enter your payment: ");
prw.print("Please enter your payment: ");
payment = keyboard.nextDouble();
// variables
cokewdeposit = (deposit * numcoke);
tshirtcost = (tshirt * numshirt);
chipscost = (chips * numchips);
cokecost = (coke * numcoke);
subtotal = (tshirtcost + chipscost + cokecost + cokewdeposit);
discount = (sale * subtotal);
total = subtotal + (subtotal * tax) - discount;
change = payment - total;
// calculation
System.out.println("Your total is $" + total);
prw.print("Your total is $" + total);
System.out.println(name + "here is your receipt");
prw.print(name + "here is your receipt");
System.out.println("item," + " " + "unit price," + " " + "how many," + " " + "cost");
prw.print("item," + " " + "unit price," + " " + "how many," + " " + "cost");
System.out.println("T-shirt ");
prw.print("T-shirt ");
System.out.print(tshirt + " " + numshirt + " " + (tshirt * numshirt));
prw.print(tshirt + " " + numshirt + " " + (tshirt * numshirt));
System.out.println("Chips ");
prw.print("Chips ");
System.out.print(chips + " " + numchips + " " + (chips * numchips));
prw.print(chips + " " + numchips + " " + (chips * numchips));
System.out.println("Coke" + coke);
prw.print("Coke" + coke);
System.out.print(coke + " " + numcoke + " " + (coke * numcoke));
prw.print(coke + " " + numcoke + " " + (coke * numcoke));
// receipt
System.out.println("Discount " + subtotal);
prw.print("Discount " + subtotal);
System.out.println("Discount " + discount);
prw.print("Discount " + discount);
System.out.println("Tax " + tax);
prw.print("Tax " + tax);
System.out.println("Total " + total);
prw.print("Total " + total);
System.out.println("Payment " + payment);
prw.print("Payment " + payment);
System.out.println("Your change is " + change);
prw.print("Your change is " + change);
System.out.println("Thank you. Come again!");
prw.print("Thank you. Come again!");
keyboard.close();
prw.close();
}
}
答案 0 :(得分:4)
你拥有的大块代码不属于main,因此永远不会被调用。你必须要么1)放入main,要么2)放入从main调用的函数。
现在你只需要在太空中悬挂代码,而你就没有调用它。
对于初学者来说,或许围绕着它:
private static void foo(){
// stick block of code in here
}
然后从main调用它:
public static void main(String [] args){
foo();
}
答案 1 :(得分:0)
快速添加接受的答案。
您编写的代码实际上是所谓的“初始化块”,它完全有效。然而,它通常用于“初始化”变量等。你可以用它们做什么有限制。 (生成线程等问题。)
即:
int a = 0;
{
//Your code
a=3;
}
内部代码由编译器在编译时执行,但它并不意味着处理代码生成。只有变量初始化。下面使用“static”关键字的例子可以让你执行一些代码,但通常没有必要。
int a=0;
static {
//Your code
a= 3;
// Other stuff
}
更好的计划是如何做到miss.serena说。 Here's一个解释初始化块如何工作的链接。