C++作业3

项目二、本月有几天

#include<stdio.h>
void main()
{
	int dYear,dMonth;
	scanf("%d%d",&dYear,&dMonth);h
	if(dMonth==1||dMonth==3||dMonth==5||dMonth==7||dMonth==8||dMonth==10
		||dMonth==12)
	printf("%d",31);
	else if(dMonth==2&&(dYear%400==0||dYear%100!=0&&dYear%4==0))
	printf("%d",29);
	else if(dMonth==2&&(dYear%400!=0&&dYear%100==0||dYear%4!=0))
	printf("%d",28);
	else
	printf("%d",30);
}

项目三、定期利息存款计算器

#include<iostream.h>
void main()
{
    double dDeposit,dInterest,dSum;
    int dNumber;
    cout<<"欢迎使用利息计算器!"<<endl;
    cout<<"请输入存款金额："<<endl;
    cin>>dDeposit;
    cout<<"======存款限期======"<<endl;
    cout<<"1.三个月"<<endl;
	cout<<"2.六个月"<<endl;
	cout<<"3.一年"<<endl;
	cout<<"4.二年"<<endl;
	cout<<"5.三年"<<endl;
	cout<<"6.五年"<<endl;
	cin>>dNumber;
	cout<<"请输入你的存款期限的代号："<<dNumber<<""<<endl;
	switch(dNumber)
	{ 
	case 1:dInterest=dDeposit*0.031*0.25;break;
	case 2:dInterest=dDeposit*0.033*0.5;break;
	case 3:dInterest=dDeposit*0.035*1;break;
	case 4:dInterest=dDeposit*0.044*2;break;
	case 5:dInterest=dDeposit*0.05*3;break;
	case 6:dInterest=dDeposit*0.055*5;break;
	default:cout<<"error";break;
	}
	dSum=dInterest+dDeposit;
	cout<<"到期利息为:"<<dInterest<<"元,本息合计共"<<dSum<<"元。"<<endl;	
}

项目4：多分段函数求值

#include<iostream.h>
#include<cmath>
void main()
{
	double x,y;
	cin>>x;
	if(x<2)
	y=x;
	else if(2<=x&&x<6)
	y=x*x+1;
	else if(6<=x&&x<10)
	y=sqrt(x+1);
	else
	y=1/(x+1);
	cout<<y;
}