逻辑错误 - 总和计算错误

Question

我正在编写一个模拟商店的程序。问题是，当我尝试获取总数时，它只给出我购买的最后一件商品的总数，而不是购买的所有商品的总数。我做错了什么以及我可以解决什么？

import java.util.Scanner;

public class Invoice {
    
public static String partNum;
public String description;
public int quantity;
public double price;


    public String part_description(String parts){
                partNum=parts;
                
                if(parts.equals("10")){
                    description="This is a large metal hammer, $20";price=20;}
                else if(parts.equals("15")){description="This is a small plastic hammer, $5";price= 5;}
                else if(parts.equals("20")){description="This is a medium wooden hammer, $10";price=10;}
                else if(parts.equals("25")){description="This is a bucket of paint, $25";price=25;}
                else{description="No such part number exists.";}
                return description; 
    }
    public void setquantity(int amount){
        quantity=amount;
        
    }
    public int getquantity(){
        
        return quantity;
    }
    public void setprice(double cost){
        price=cost;
        if(cost<0){cost=0;}
        
    }
    public double getprice(){
        return price;
    }
    public double getInvoiceAmount(double total){
        total=total+(quantity*price);
        return total;
    }
    
    public static void main(String[] args){
        
        Scanner s1= new Scanner(System.in);
        Invoice invoiceObject= new Invoice();
        boolean ask=true;
        while(ask==true){
            
        
        System.out.println("Chose one of the fallowing part numbers: 10, 15, 20, 25");
        
         partNum=s1.nextLine();
        
        System.out.println(invoiceObject.part_description(partNum));
        
        System.out.printf("\nHow many #%s would you like to get: ", partNum);
        int numOf=s1.nextInt();
        invoiceObject.setquantity(numOf);
        
        System.out.println("would you like to keep shopping? chose true or false");
        ask=s1.nextBoolean();
        partNum=s1.nextLine();
        
        }
        System.out.println("Your total price will be:$ "+invoiceObject.getInvoiceAmount(0));
}}

Answer 1

您实际上永远不会在任何地方将总价格相加。您需要有一个变量，例如totalSum。您希望在用户开始执行任何操作之前将其设置为 0。然后你想提高价格。

//pseudo code.
totalSum = totalSum + (quantity*price)

//at the end
print(totalSum)