Question

Java使用字符串生成器来保存购物车中的商品信息，并能实现商品信息的添加、删除以及修改等功能

怎么实现方法 show()，可以将购物车中所有的商品信息输出，
并显示购物车中商品的总价。 急求帮助！！！谢谢！！以下是代码：
public class Goods {
public String gname;
public float gprice;
public int gnum;
public float gtotal;

}
public class Cart {
public StringBuilder data;
public float total;
public Cart(){
data=new StringBuilder();
}
public void buy(Goods g){
g.gtotal=g.gnum*g.gprice;
total=total+g.gtotal;
data.append("[");
data.append(g.gname+":");
data.append(g.gprice+":");
data.append(g.gnum+":");
data.append(g.gtotal);
data.append("]");
}
public void delete(Goods g){
int s=data.indexOf(g.gname);
int e=data.indexOf("]", s);
data.delete(s-1, e+1);
}
public void update(Goods g){
data.replace(3, 10, "["+g.gname+":"+g.gprice+":"+g.gnum+":"+g.gtotal);
}
public void show(){

}
public class Execute {

public static void main(String[] args) {
// TODO Auto-generated method stub
Goods g1=new Goods();
g1.gname="皮鞋";
g1.gprice=800;
g1.gnum=1;
Goods g2=new Goods();
g1.gname="唇膏";
g1.gprice=350;
g1.gnum=2;
Cart cart=new Cart();
cart.buy(g1);
cart.buy(g2);
cart.show();
cart.delete(g1);
cart.show();
}

}

Answer 1

public class Cart {
    public StringBuilder data;
    public float total;
    public Cart(){
        data=new StringBuilder();
    }
    public void buy(Goods g){
        g.gtotal=g.gnum*g.gprice;
        total=total+g.gtotal;
        data.append("[");
        data.append(g.gname+"|");
        data.append(g.gprice+"|");
        data.append(g.gnum+"|");  //还是竖线看着方便
        data.append(g.gtotal);
        data.append("]");
    }
    public void delete(Goods g){
        int s=data.indexOf(g.gname);
        int e=data.indexOf("]", s);
        data.delete(s-1, e+1);
        total=total-g.gtotal;  //删除商品 ，需要修改总额
    }
    public void update(Goods g){
        data.replace(3, 10, "["+g.gname+"|"+g.gprice+"|"+g.gnum+"|"+g.gtotal);
    }
    public void show(){
        System.out.print("总计金额：" + total + "    ") ;
        System.out.println(data);
    }
}


//Excute类里有点小错误，
//总觉得update方法 不对头，你想怎么做？

追问

没事了，已经解决了，谢谢
另外测试了下，update方法是可行的