C++作业3

#include <iostream>
#include<cmath>
using namespace std;
int main()
{
double x,y;
cout<<"请输入x的值:";
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的值为:"<<y<<endl;
return 0;
}

#include<iostream>
using namespace std;
int main()
{
int y;
double x,z,m;
cout<<"欢迎使用利息计算器!"<<endl;
cout<<"请输入存款金额:";
cin>>x;
cout<<"======存款期限======\n1.3个月\n2.6个月 \n3.一年\n4.二年\n5.三年\n6.五年"<<endl;
cout<<"请输入存款期限的代号";
cin>>y;
switch(y)
{
case 1:z=x*0.031*0.25;break;
case 2:z=x*0.033*0.5;break;
case 3:z=x*0.035*1;break;
case 4:z=x*0.044*2;break;
case 5:z=x*0.05*2;break;
case 6:z=x*0.055*5;break;
default:cout<<"error\n";break;
}
m=x+z;
cout<<"到期的利息为"<<z<<"元,本息合计为"<<m<<"元"<<endl;
cout<<"感谢您的使用，欢迎下次光临！"<<endl;
return 0;
}

#include<iostream>
using namespace std;
int main()
{
int Y,M,D;
cout<<"请输入年份和月份:";
cin>>Y>>M;;
if((Y%4==0&&Y%100!=0)||Y%400==0&&M==2) D=29;
else D=28;
if(M==1||M==3||M==5||M==7||M==8||M==10||M==12) D=31;
if(M==4||M==6||M==9||M==11) D=30;
cout<<"该月的天数为："<<D<<endl;
return 0;
}