C++作业3

#include<iostream>
using namespace std;
int main()
{
//四年一闰，百年不闰，四百年再闰;
int year,month,day;
cout<<"欢迎试用万氏日历!"<<endl;
cout<<"请输入年份";
cin>>year;
cout<<"请输入月份";
cin>>month;
switch(month)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: day=31;break;
case 4:
case 6:
case 9:
case 11: day=30;break;
case 2:
if( year%400==0 || (year%4==0 && year%100!=0))
day=29;
else day=28;break;
default : cout<<"Error"<<endl;
}
cout<<"该月有"<<day<<"天"<<endl;
return 0;
}

#include<iostream>
using namespace std;
int main()
{
cout<<"欢迎使用万氏利息计算器!"<<endl;
cout<<"请输入存款金额：\0"<<" ";
int money,number;
double interest,rate,term,sum;
//interest:利息；sum：金额；rate:利率；term:存期
cin>>money;
cout<<"=======存款期限======="<<endl;
cout<<"1. 3个月\n2. 6个月\n3. 一年\n4. 两年\n5. 三年\n6. 五年"<<endl;
cout<<"请输入存款期限的代号：";
cin>>number;
switch(number)
{
case 1: term=0.25;rate=0.031;break;
case 2: term=0.50;rate=0.033;break;
case 3: term=1.00;rate=0.035;break;
case 4: term=2.00;rate=0.044;break;
case 5: term=3.00;rate=0.050;break;
case 6: term=5.00;rate=0.055;break;
default : cout<<"对不起，无此选项"<<endl;
}
interest=money*term*rate;
sum=money+interest;
cout<<"到期利息为："<<interest<<","<<"本息合计共："<<sum<<"元"<<endl;
cout<<"感谢您的使用，欢迎下次光临!"<<endl;
return 0;
}

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