求C++经典程序

最开始学c++，第一个遇到的程序一般都为
#include <iostream>
using namespace std;

int main()
{
cour<<"hollo,world!"<<endl;
return 0;
}

再接着就是如比较两个数大小的（略）
下面给你一个比较简单的判断某年某月某日是本年的第几天：
#include <iostream>
using namespace std;
int dayfun (int nowyear,int nowmonth,int nowday)
{
bool isrunnian=(((nowyear%4==0)&&(nowyear%100!=0))||(nowyear%400==0));
int whichday=0;
for (int i=1;i<nowmonth;i++)
{
switch(i){
case 1: case 3: case 5: case 7: case 8: case 10: case 12:
{whichday+=31;break;}
case 4: case 6:case 9: case 11:
{whichday+=30;break;}
case 2:
if(isrunnian==true)
{whichday+=29;break;}
else
{whichday+=28;break;}
}
}
return whichday+nowday;
}

int main()
{
int nowyear,nowmonth,nowday,ff=0;
cout<<"请输入一个日子:&quo