c++第3次作业

一.本月有几天

#include<iostream>
using namespace std;
int main()
{

	int month,year,days;
	cout<<"请输入年份,月份:"<<endl;
	cin>>year>>month;
	{
		if(month==1||month==3||month==5||month==7||month==8||month==10||month==12)
		    days=31;
		else if(month==4||month==6||month==9||month==11)
			days=30;
		else
		{
			if((year%4==0&&year%100!=0)||year%400==0)
				days=29;
			else
				days=28;
		}
	}
		cout<<"天数为："<<days<<"天"<<endl;
		return 0;

}

二.定期存款利息计算器

#include<iostream>
using namespace std;
int main()
{
	int m,x;
	cout<<"欢迎使用利息计算器\n";
	cout<<"请输入存款金额=";
	cin>>m;
	cout<<"==========存款期限===========\n";
    cout<<"1、3个月\n";
	cout<<"2、6个月\n";
	cout<<"3、一年\n";
	cout<<"4、两年\n";
	cout<<"5、三年\n";
	cout<<"6、五年\n";
	cout<<"请输入存款期限代号:";
	cin>>x;
	switch(x)
	{
	double a,z;
	case 1:a=m*0.031*0.25,z=m+a;
		cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	case 2:a=m*0.033*0.5,z=m+a;
        cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	case 3:a=m*0.035*1,z=m+a;
        cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	case 4:a=m*0.044*2,z=m+a;
        cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	case 5:a=m*0.05*3,z=m+a;
        cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	case 6:a=m*0.055*5,z=m+a;
        cout<<"到期利息:"<<a<<"元,本息合计共:"<<z<<"元。"<<endl;break;
	default:cout<<"error\n";
	}
	cout<<"感谢您的使用，欢迎下次光临！\n";
	return 0;
}

三.多分数段函数求值

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
	double x,y;
	cout<<"请输入x=";
	cin>>x;
	if(x<2)
		y=x;
	else if(x<6)
		y=x*x+1;
	else if(x<10)
		y=sqrt(x+1);
	else
		y=1/(x+1);
	cout<<"y="<<y<<endl;
	return 0;
}