c++第三次作业

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

#include<iostream>
using namespace std;
int main()
{
int a,b,c;
cout<<"请输入存款金额";cin>>a;
cout<<"请选择存款期限，1、三个月\n2、六个月\n3、一年\n4、两年\n5、三年\n6、五年\n请输入存款期限的代号";cin>>b;
switch(b)
{
case 1:c=a*(1+0.031)*0.25;break;
case 2:c=a*(1+0.035)*0.5;break;
case 3:c=a*(1+0.035)*1;break;
case 4:c=a*(1+0.044)*2;break;
case 5:c=a*(1+0.050)*3;break;
case 6:c=a*(1+0.055)*5;break;
}
cout<<"到期利息为:"<<c-a<<endl;
cout<<"总计为:"<<c;
}

#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=2;
else {
if(x<6)
y=x*x+1;
else{
if(x<10)
y=sqrt(x+1);
else
y=1/(x+1);
}
}
cout<<"y="<<y;
return 0;
}