c++作业3

#include<iostream>
using namespace std;
int main()
{
int year,month,days;
cout<<"	请输入年份";
cin>>year;
cout<<"请输入月份";
cin>>month;
if(month==2)
{
if((year%4==0&&year%100!=0)||(year%400==0))
days=29;
else
days=28;
}
else
switch(month)
{
case'1':
case'3':
case'5':
case'7':
case'8':
case'10':
case'12':cout<<"这个月有31天\n";
break;
case'4':
case'6':
case'9':
case'11':cout<<"这个月有30天\n";
break;
}
cout<<"这个月有<<days<<"天"<<endl;
return 0;
}

#include<iostream>
using namespace std;
int main()
{
int x;
double money,rate,interest,sum;
cout<<"欢迎使用利息计算器"<<endl;
cout<<"请输入存款金额:"<<endl;
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;
cin>>x;
switch (x)
{
case 1:rate=0.0031*0.25;break;
case 2:rate=0.0033*0.5;break;
case 3:rate=0.0035*1;break;
case 4:rate=0.0044*2;break;
case 5:rate=0.0050*3;break;
case 6:rate=0.0055*5;break;
default:cout<<"error\n";break;
}
interest=money*rate;
sum=money+interest;
cout<<"到期利息为："<<interest<<"元，"<<"本息合计共"<<sum<<"元。"<<endl;
cout<<"感谢您的使用，欢迎下次光临！";
return 0;
}

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