c++第三次作业

项目二

#include <iostream>  using namespace std;  int main()  {      int year,month;      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: cout<<"本月共有31天\n";break;      case 4:      case 6:      case 9:      case 11: cout<<"本月共有30天\n";break;      case 2:          if(year%400==0||year%4==0&&year%100!=0)              cout<<"本月共有29天"<<endl;          else cout<<"本月共有28天"<<endl;      }      return 0;  } 

项目三

#include<iostream>  using namespace std;  int main()  {      int type;      double money,period,rate,w;      cout<<"欢迎使用利息计算器!"<<endl;      cout<<"请输入存款金额:";      cin>>money;      cout<<"======存款金额======"<<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;     cout<<"请输入存款期限的代号:";     cin>>type;      if(type>=1&&type<=6)      {          switch(type)         {          case 1:period=0.25;rate=0.031;break;          case 2:period=0.5;rate=0.033;break;          case 3:period=1;rate=0.035; break;          case 4: period=2;rate=0.044;break;         case 5:period=3;rate=0.05;break;          case 6:period=5;rate=0.055;break;          }     w=money*period*rate;      cout<<"到期利息为:"<<w<<"元，本息合计共"<<w+money<<"元。"<<endl;     }  else   cout<<"选择存款类型错误!"<<endl;  cout<<"感谢您的使用，欢迎下次光临!"<<endl;  return 0;  }  

项目四

#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=x;      else if(x>=2&&x<6) y=x*x+1;      else if(x>=6&&x<10) y=sqrt(x+1);      else if(x>=10) y=1/(x+1);      cout<<"请输入y的值:"<<y<<endl;    return 0;  }