年历输出

标准输出某年的日历，要求星期和日期对应

//转自：http://bbs.csdn.net/topics/390284667#include <stdio.h>#include <math.h>void printmonth(int m);void printhead(int m);int daysofmonth(int m);int firstday(int y);int year,weekday;int main(){    int i;    printf("请输入年份：\n");    scanf("%d", &year);    weekday=firstday(year);  //计算某年元旦是星期几    printf("\n\n");    printf("                 %d年\n",year);    for(i=1;i<=12;i++)    {        printmonth(i);        printf("\n");    }    printf("\n\n");    return 0;}void printmonth(int m){    int i,days;    printhead(m);    days=daysofmonth(m);    for(i=1;i<=days;i++)    {        printf("%5d",i);        weekday=(weekday+1)%7;        if (weekday==0) printf("\n   ");    }}void printhead(int m){    int i;    printf("\n%d月   日   一   二   三   四   五   六\n",m);    printf("   ");    for(i=0;i<weekday;i++)        printf("     ");}int daysofmonth(int m){    switch (m)    {    case 1:    case 3:    case 5:    case 7:    case 8:    case 10:    case 12:return 31;    case 4:    case 6:    case 9:    case 11:return 30;    case 2:if (((year%4==0 && year%100!=0)||year%400==0))               return 29;        else            return 28;    default: return 0;    }}//计算某年元旦是星期几int firstday(int y){    double s;    s = floor((y-1) + (y-1)/4 - (y-1)/100 + (y-1)/400 + 1);    return (int)s%7;}