这个问题如何实现?怎样写代码!java

Question

问题如下:  
 
/*  
 有一间书店,新出一种收,单价是24.5元一本.若一次性购买100本或以上,则打8折.          
若一次性购买200本或以上,则打7.5折.  若一次性购买500本或以上,刚打7折.          
现在要写一个程序,从控制台接受要购买的数量,输出需要的金额.    
*/    
   
相关程序:(在jdk下运行通过)  
 
import  java.io.*;  
public    class    Book{      
         public    static    void    main(String[]  args)      
                     {      
                         int    i;  
                         String  s="";  
                         System.out.println("请输入购买数量：");  
                         try{  
                               BufferedReader  in  =new  BufferedReader(new  InputStreamReader(System.in));  
                               s=in.readLine();                                                              
                         }catch(IOException  e){}  
                         i=Integer.parseInt(s);  
         if(i<100)      
                     {      
             System.out.println(24.5*i);      
                       }      
         if(i>=100&&i<200)      
               {      
             System.out.println(24.5*i*0.8);      
               }      
         if(i>=200&&i<500)      
               {      
                 System.out.println(0.75*24.5*i);      
               }      
         if(i>=500)      
               {      
               System.out.println(0.7*24.5*i);    
                     }  
}  
}  
 
我的问题:  
每次在运行的时候,输入购买数量,程序会根据条件计算出费用!  
怎样加一个转移语句,实现在第一次操作之后,提示是否进行费用计算?(y/n);  
如果输入y  提示请输入购买数量!进行计算!  
如果输入n  提示结束本次操作!  
 
谢谢了,小弟是java初学者!  
最好给我一个完善的程序!  
3Q!

Answer 1

public class Book
{
public static void main(String[] args){
Book b = new Book();
b.calculate();
} public void calculate()
{
int    i;  
        String  s="";  
boolean flag = true;
while (flag)
{
System.out.println("请输入购买数量：");  
try{  
BufferedReader  in  =new  BufferedReader(new  InputStreamReader(System.in));  
s=in.readLine();                                                              
}catch(IOException  e){}  

if (!doCalculate())
{
return;
} i=Integer.parseInt(s);  
if(i<100)      
{      
System.out.println(24.5*i);      
}      
if(i>=100&&i<200)      
{      
System.out.println(24.5*i*0.8);      
}      
if(i>=200&&i<500)      
{      
System.out.println(0.75*24.5*i);      
}      
if(i>=500)      
{      
System.out.println(0.7*24.5*i);    
} 
flag = again();
}         
} private boolean doCalculate()
{
try
{
System.out.println("是否进行费用计算？");
BufferedReader  in  =new  BufferedReader(new  InputStreamReader(System.in));  
            s=in.readLine();                                                              
if (s.equals("Y"))
{
return true;
}
else
{
return false;
}
        }catch(IOException  e){}
return false;
} private boolean again()
{
try
{
System.out.println("是否继续输入？");
BufferedReader  in  =new  BufferedReader(new  InputStreamReader(System.in));  
            s=in.readLine();                                                              
if (s.equals("Y"))
{
return true;
}
else
{
return false;
}
        }catch(IOException  e){}
return false;
}
};

Answer 2

import  java.io.*;  
public    class    Book{      
         public    static    void    main(String[]  args)      
                     {      
                         int    i; 
                         
                         String  s=""; 
                         String  s2=""; 
             do{
                         
                         System.out.println("请输入购买数量：");  
                         try{  
                               BufferedReader  in  =new  BufferedReader(new  InputStreamReader(System.in));  
                               s=in.readLine();                                                              
                         }catch(IOException  e){}  
                         i=Integer.parseInt(s);  
         if(i<100)      
                     {      
             System.out.println(24.5*i);      
                       }      
         else if(i>=100&&i<200)      
               {      
             System.out.println("8折 "+24.5*i*0.8);      
               }      
         else if(i>=200&&i<500)      
               {      
                 System.out.println("75折 "+0.75*24.5*i);      
               }      
         else if(i>=500)      
               {      
               System.out.println("7折 "+0.7*24.5*i);    
                     }  
              System.out.println("继续计算？");
              try{BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
              s2=in.readLine();
              }catch(IOException e){
              }
              
                     
            }while(s2.equals("y"));
}  
}  
把你的程序改了一下

Answer 3

import java.io.*;
public class Book { /**
 * @param args
 */
public static void main(String[] args) {
// TODO Auto-generated method stub
int i;
String flag = "Y";
String  s = "";
BufferedReader in = null;
while (flag.toUpperCase().equals("Y")) {
System.out.println("请输入购买数量：");  
try{  
in = new BufferedReader(new InputStreamReader(System.in));  
s=in.readLine();                 
} catch (IOException  e){

}  
i=Integer.parseInt(s);  
if(i < 100) {
System.out.println(24.5*i);
} 
if(i >= 100 && i < 200) {   
System.out.println(24.5*i*0.8);   
}   
if(i >= 200 && i < 500) {   
System.out.println(0.75*24.5*i);   
}   
if(i >= 500) {   
System.out.println(0.7*24.5*i); 
}

System.out.println("提示是否进行费用计算?(y/n):");
try{
flag = in.readLine();
} catch (IOException  e) {

}
}
}}
Thanks
Hima

Answer 4

import java.io.*;public class Example10 {
    public static void main(String[] args) {
        int i = 0;
        String again = "Y";
        try {
            while (again == "Y") {
                System.out.println("请输入购买数量：");
                BufferedReader in = new BufferedReader(new InputStreamReader(
                        System.in));
                i = Integer.parseInt(in.readLine());                if (i < 100) {
                    System.out.println(24.5 * i);
                }
                if (i >= 100 && i < 200) {
                    System.out.println(24.5 * i * 0.8);
                }
                if (i >= 200 && i < 500) {
                    System.out.println(0.75 * 24.5 * i);
                }
                if (i >= 500) {
                    System.out.println(0.7 * 24.5 * i);
                }
                System.out.println("是否进行费用计算?(y/n):");
                if (in.readLine().toUpperCase().equals("N")) {
                    again = "N";
                    System.out.println("结束计算！");
                }
            }
        } catch (IOException e) {
            System.err.println(e);
        }    }
}