C++作业3——本月有几天、定期存款利息计算器、多分数段函数求值

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

#include<iostream>
using namespace std;
int main()
{
int b;
double a,c,d,e,f;
cout<<"欢迎使用利息计算器！"<<endl;
cout<<"请输入存款金额:";
cin>>a;
cout<<"======存款期限======\n"<<"1.3个月\n"<<"2.6个月\n"<<"3.一年\n"<<"4.二年\n"<<"5.三年\n"<<"6.五年\n";
cout<<"请输入存款期限代号：";
cin>>b;
switch(b)
{
case 1:
c=0.0310,d=0.25;
break;
case 2:
c=0.0330,d=0.50;
break;
case 3:
c=0.0350,d=1.00;
break;
case 4:
c=0.0440,d=2.00;
break;
case 5:
c=0.0500,d=3.00;
break;
case 6:
c=0.0550,d=5.00;
break;
}
e=a*c*d;
f=a+e;
cout<<"到期利息为："<<e<<"元，本息合计共"<<f<<"元";
return 0;
}

#include <iostream>
#include <cmath>
using namespace std;
int main( )
{
int x,y;
cout<<"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 if(x>=10)
{
y=1/(x+1);
}
cout<<"y的值为;"<<y<<endl;
return 0;
}