poj 2521 How much did the businessman lose

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How much did the businessman lose

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 10930 Accepted: 7123

Description

Businessmen, of course, can make much money. However, sometimes, they would lose money in trading. For example, Jame, a businessman, brought in some goods each cost him 40 yuan and he decided to sell at the price of 70 yuan. Then a customer came to buy one, gave Jame 100 yuan, and of course got back 30 yuan. You may said, "Jame earned 30 yuan." But unfortunately, Jame found the 100 yuan from the customer was fake. What a poor man! In this case Jame lost 70 yuan (40 (the goods price) + 30 (the money paid back to the customer)). 

Now your task is to calculate how much Jame would lose in this kind of trade. Of course in this case, sometimes Jame may still earn. 

Input

The input consists of several instances. Each instance contains four integers N, M, P and C, which are all in the range [0, 50000], separated by a single space. 

N is the cost price of Jame good. 
M is the sell price. 
P is the total fake money the customer gave Jame. 
C is how much Jame paid back to the customer. 

Here N < M. And P may be less than M, as customer may pay with some fake money and some true money. 

The input is terminated by a line containing 4 zeros. 

Output

For one instance, output one line contains exactly one integer, which tells how much Jame lost in the trade. If Jame still earned, just output a negative integer, the absolute value of which tells the money Jame earned.

Sample Input

40 70 100 3040 70 50 2014604 32391 3902 1530 0 0 0

题目解析：

本题的大概意思是，一个商人卖货收到价钱，计算最终赔了多少或者赚了多少。

我的解决办法是，

1，先计算商人从腰包里拿出来多少钱，也就是商品的进货价格+付给客户的价格

2，接下来计算商人得到的真钱有多少，也就是商人给客户的钱+商品的售价-商人给的假钱

3，最后计算两个的差值，就是所要求得。

再计算

代码：

#include<iostream>using namespace std;int main(){    int N,M,P,C;    while(cin>>N>>M>>P>>C&&N!=0||M!=0||P!=0||C!=0)    {        cout<<N+C-(M+C-P)<<endl;    }    return 0;}