【C学习笔记】C_Primer_Plus6 练习 商店收银台结算系统

C Primer Plus6 第216页 练习11：

ABC 邮购杂货店出售的洋蓟售价为 2.05 美元/磅，甜菜售价为 1.15 美元/磅，胡萝卜售价为 1.09美元/磅。在添加运费之前，100美元的订单有5%的打折优惠。少于或等于5磅的订单收取6.5美元的运费和包装费，5磅～20磅的订单收取14美元的运费和包装费，超过20磅的订单在14美元的基础上每续重1磅增加0.5美元。编写一个程序，在循环中用switch语句实现用户输入不同的字母时有不同的响应，即输入a的响应是让用户输入洋蓟的磅数，b是甜菜的磅数，c是胡萝卜的磅数，q 是退出订购。程序要记录累计的重量。即，如果用户输入 4 磅的甜菜，然后输入 5磅的甜菜，程序应报告9磅的甜菜。然后，该程序要计算货物总价、折扣（如果有的话）、运费和包装费。随后，程序应显示所有的购买信息：物品售价、订购的重量（单位：磅）、订购的蔬菜费用、订单的总费用、折扣（如果有的话）、运费和包装费，以及所有的费用总额。

简单地练习了一下 switch 语句：

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include<windows.h> 
#include <math.h>

void Ex11()
{
	//定义单价
	const float artichoke = 2.05f;	//洋蓟
	const float beet = 1.15f;		//甜菜
	const float carrot = 1.09f;		//萝卜

	//品种小计总价
	float price_artichoke = 0;	//洋蓟
	float price_beet = 0;		//甜菜
	float price_carrot = 0;		//萝卜

	//品种小计重量
	float weight_artichoke = 0;	//洋蓟
	float weight_beet = 0;		//甜菜
	float weight_carrot = 0;	//萝卜

	//购买的重量
	float amount;


	//产生的数据
	float totleweight = 0.0;	//总重
	float totalprice = 0.0;		//总价
	float payment = 0.0;		//最后结算金额
	float totaldiscount = 0.0;	//总折扣
	float freight = 0.0;		//运费包装费


	char type = 0; // 购买种类
	SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_INTENSITY);
	printf(\"\\t\\tABC邮购杂货店 欢迎光临\\n\");
	printf(\"商品列表：\\n\");
	printf(\"洋蓟\\t单价:%.2f元/斤\\n\", artichoke);
	printf(\"甜菜\\t单价:%.2f元/斤\\n\", beet);
	printf(\"萝卜\\t单价:%.2f元/斤\\n\", carrot);
	SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE);
	
	while (1)
	{
		printf(\"\\n请输入你要购买的产品：[ a=洋蓟 b=甜菜 c=萝卜 q=结算/退出]：\");
		//scanf(\"%c\",&type);
		type = getchar();
		switch (type)
		{
		case \'a\':
		case \'A\'://洋蓟
			printf(\"请输入你要购买\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_INTENSITY);
			printf(\"洋蓟\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE);
			printf(\"的重量（磅）：\");
			scanf(\"%f\", &amount);
			weight_artichoke += amount;
			price_artichoke += amount * artichoke;
			break;
		case \'b\':
		case \'B\'://甜菜
			printf(\"请输入你要购买\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_INTENSITY);
			printf(\"甜菜\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE);
			printf(\"的重量（磅）：\");
			scanf(\"%f\", &amount);
			weight_beet += amount;
			price_beet += amount * beet;
			break;
		case \'c\':
		case \'C\'://萝卜
			printf(\"请输入你要购买\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_INTENSITY);
			printf(\"萝卜\");
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE);
			printf(\"的重量（磅）：\");
			scanf(\"%f\", &amount);
			weight_carrot += amount;
			price_carrot += amount * carrot;
			break;
		case \'q\':
		case \'Q\'://退出
			//结算数据：

			//总重量：
			totleweight = weight_artichoke + weight_beet + weight_carrot;
			//小计购买金额
			totalprice = price_artichoke + price_beet + price_carrot;

			//少于5磅，收6.5元的运费和包装费;
			if (totleweight <= 5) freight += 6.5;
			if (totleweight > 5 && totleweight <= 20) freight += 14;
			//大于20磅，每续重1磅就增加0.5元
			if (totleweight > 20) 
			{
				freight += 14;
				freight += (float)(round(totleweight - 20) * 0.5); //需要四舍五入;
			}
			//100美元有5%的优惠;
			if (totalprice >= 100) totaldiscount = (float)(totalprice*0.05);

			//最后得出应付总金额
			payment = totalprice + freight - totaldiscount;  

			printf(\"\\n结算数据如下：\\n\");
			printf(\"\\t商品名\\t单价\\t重量\\t小计金额\\n\");
			printf(\"----------------------------------------------------------\\n\");
			if (weight_artichoke>0) printf(\"\\t洋蓟\\t%.2f\\t%.2f\\t%.2f\\n\", artichoke, weight_artichoke, price_artichoke);
			if (weight_beet>0) printf(\"\\t甜菜\\t%.2f\\t%.2f\\t%.2f\\n\", beet, weight_beet, price_beet);
			if (weight_carrot>0) printf(\"\\t萝卜\\t%.2f\\t%.2f\\t%.2f\\n\", carrot, weight_carrot, price_carrot);
			printf(\"-----------------------------------------------------------\\n\");
			printf(\"\\t小计\\t\\t%.2f\\t%.2f\\n\", totleweight, totalprice);
			printf(\"购买总金额：%.2f\\n\",totalprice);
			printf(\"包装费运费：%.2f\\n\",freight);
			printf(\"折扣：%.2f\\n\",totaldiscount);
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_INTENSITY);
			printf(\"总金额：%.2f\\n\", payment);
			SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE);

			printf(\"\\n欢迎再次光临！\\n\");
			system(\"pause\");
			return; //退出；
		default:
			printf(\"你购买的商品不存在，请重新输入。\\n\");
		}
		fflush(stdin); //清缓存
	}
}

int main()
{
	Ex11();
	return 0;
}

测试运行结果：

其中添加了对控制台字体颜色的控制。