1.1.3 Friday the Thirteenth

         简单题……

#include<iostream>
#include<fstream>
using namespace std;
int main()
{
	int n, num[8]={0}, days;
	int mon[13]={0, 31,28,31,30,31,30,31,31,30,31,30,31 };
	
    ifstream fin("friday.in");
    ofstream fout("friday.out");
	//cin>>n;
	fin>>n;
	
	days=12;
	
	n+=1900;
	int i, j;
	for(i=1900; i<n; i++)
    {
    	for(j=1; j<=12; j++)
    	{
    		num[days%7]++;	
	    	days+=mon[j];
	    	
	    	if( j==2 && (i%100!=0&&i%4==0 || i%400==0))//注意，不应该为j==3 
	    	    days+=1;
	    }
    }
	fout<<num[5]<<" "<<num[6];
	for(i=0; i<5; i++)
	    fout<<" "<<num[i];
    fout<<endl;	
} 

而且：

另解：

//这个模板本来是求某年某月某天为星期几的；注释部分判断1752年9月3日前的
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
    int n, i, j, a, day, num[8]={0}, month, year;
    
    ifstream fin("friday.in");
    ofstream fout("friday.out");
    fin>>n;
    n+=1900;
    day=13;
    
    for(i=1900; i<n; i++)
	{
		for(j=1; j<=12; j++)
		{
			year=i;
			month=j;
			//1,2月当做前一年的13,14月
			if( month==1 || month==2)
			{
				year--;
				month+=12;	
			}
			//判断是否在1752年9月3日之前

		//	if( year<1752 || (year==1752 && month<9) || (year==1752 && month==9 && day<3) )
			//	a=(day+2*month+3*(month+1)/5+year+year/4+5)%7;
		//	else
			    a=(day+2*month+3*(month+1)/5+year+year/4-year/100+year/400)%7;
			num[a]++;
		}
	}
	
	fout<<num[5]<<" "<<num[6]; 
	for(i=0; i<5; i++)
		fout<<" "<<num[i];
	fout<<endl;
}