后期加工，成为一个实用的功能，这里作为一个demo,进行记录。

#include<iostream>  
using namespace std;
int main()
{
	int  type;
	double money, period, rate, interest;
	cout << "欢迎使用利息计算器！" << endl;
	cout << "请输入存款金额：";
	cin >> money;
	cout << "======存款期限======" << endl;
	cout << "1. 3个月 " << endl;
	cout << "2. 6个月" << endl;
	cout << "3. 一年 " << endl;
	cout << "4. 二年" << endl;
	cout << "5. 三年" << endl;
	cout << "6. 五年" << endl;
	cout << "请输入存款期限的代号：";
	cin >> type;
	if (type >= 1 && type <= 6)
	{
		switch (type)   //在if中嵌入了switch分情况处理  
		{
		case 1:
			period = 0.25;
			rate = 0.031;
			break;
		case 2:
			period = 0.5;
			rate = 0.033;
			break;
		case 3:
			period = 1;
			rate = 0.035;
			break;
		case 4:
			period = 2;
			rate = 0.044;
			break;
		case 5:
			period = 3;
			rate = 0.05;
			break;
		case 6:
			period = 5;
			rate = 0.055;
			break;
		}
		interest = money * period * rate;
		cout << "到期利息为：" << interest << "元，本息合计共" << interest + money << "元。" << endl;
	}
	else
		cout << "选择存款类型错误！" << endl;
	cout << "感谢您的使用，欢迎下次光临！" << endl;
	system("pause");
	return 0;
}