C++作业3

#include <iostream.h>
#include <cmath>
void 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 if (x>=10) y=1/(x+1);
cout<<"y的值为"<<y<<endl;
return0
}

#include <iostream>
using namespace std;
int main()
{
int a,b;
cout<<"请输入年份"<<endl;
cin >>a;
cout<<"请输入月份"<<endl;
cin >>b;
if(b==1||b==3||b==5||b==7||b==8||b==10||b==12)
cout<<"该月有31天"<<endl;
else if(b==4||b==6||b==9||b==11)
cout<<"该月有30天"<<endl;
else if(b=2)
{
if(a%4==0&&a%100!=0||a%400==0)
cout<<"该月有29天"<<endl;
else
cout<<"该月有28天"<<endl;
}
}

#include <iostream>
using namespace std;
int main()
{
double a,b,c,d;     //a为本金；b为利息；c为年；d为利率
int e;              //存款期限
cout<<"欢迎使用利息计算器！\n"<<"请输入存款金额";
cin>>a;
cout<<"======存款期限======"<<endl;
cout<<"1. 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>>e;
switch(e)
{
case 1:c=0.25;d=0.031;break;
case 2:c=0.5;d=0.033;break;
case 3:c=1;d=0.035;break;
case 4:c=2;d=0.044;break;
case 5:c=3;d=0.05;break;
case 6:c=6;d=0.055;break;
}
b=a*c*d;
cout<<"到期利息为"<<b<<"元，本息合计为"<<a+b<<"元。"<<endl;
}