calendar.c

万年历程序（输入年份

/*输入年份，输出该年的年历*/
#include <stdio.h>
long int f(int year,int month)
{
    if(month<3) return year-1;
    else return year;
}
long int g(int month)
{
    if(month<3) return month+13;
    else return month+1;
}
long int n(int year,int month,int day)
{                         /*N=1461*f(年,月)/4+153*g(月)/5+日*/
    return 1461L*f(year,month)/4+153L*g(month)/5+day;
}
int w(int year,int month,int day)
{                       /*w=(N-621049)%7(0<=w<7)*/
    return (int) ((n(year,month,day)%7-621049L%7+7)%7);
}

int date[12][6][7];
int day_tb[][12]={{31,28,31,30,31,30,31,31,30,31,30,31},
                  {31,29,31,30,31,30,31,31,30,31,30,31}};
                  
int main()
{
    int sw,leap,i,j,k,wd,year,day;
    char title[]="SUN MON TUE WED THU FRI SAT";
    printf("Please input the year whose calendar you want to know: ");
    scanf("%d%*c",&year);
    
    sw=w(year,1,1);
    leap=year%4==0&&year%100||year%400==0; /*判闰年*/
    for(i=0;i<12;i++)
        for(j=0;j<6;j++)
            for(k=0;k<7;k++)
                date[i][j][k]=0;  /*日期表置0*/
    for(i=0;i<12;i++)
        for(wd=0,day=1;day<=day_tb[leap][i];day++)
        {               /*将第i+1月的日期填入日期表*/
            date[i][wd][sw]=day;
            sw=++sw%7;      /*每星期7天，以0~6计数*/
            if(sw==0) wd++;     /*日期表每七天一行，星期天开始新的一行*/
        }
    printf("\n|===================The calender of the year %d ================|\n|",year);
    for(i=0;i<6;i++)
    {
        for(wd=0,k=0;k<7;k++)
            wd+=date[i][5][k]+date[i+6][5][k];
        wd=wd?6:5;
        printf("%2d  %s  %2d  %s |\n|",i+1,title,i+7,title);
        for(j=0;j<wd;j++)
        {
            printf("   ");   /*3个空白符*/
            for(k=0;k<7;k++)
                if(date[i][j][k])
                    printf("%4d",date[i][j][k]);
                else printf("    ");     /*4个空白符*/
            printf("     ");   /*5个空白符*/
            for(k=0;k<7;k++)
                if(date[i+6][j][k])
                    printf("%4d",date[i+6][j][k]);
                else printf("    ");  /*4个空白符*/
            printf(" |\n|");
        }
    }
    puts("=================================================================|");
    puts("\n Press any key to quit...");
    getch();
    return 0;
}