#include<stdio.h>
int main()
{

    int firstday(int year);

    int sw,leap,i,j,k,wd,day;  
   
    int date[12][6][7];         //定义一个三维数组 分别对应 月、周、日
    char title[] = "SUN MON TUE WED THU FRI SAT";
    int day_tab[][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}
                        };        //平年和闰年的月份天数
    int year;


    printf("please input the year:");
    scanf("%d",&year);         

    sw = firstday(year);        //计算这一年的第一天是星期几
    leap = (year%4 ==0 && year%100 != 0) || year%400 ==0;
    for( i=0; i<12; i++ )
        for( j=0; j<6; j++)
            for( k=0; k<7; k++)
                date[i][j][k] = 0;   //将所有的日期都归零
    for( i=0; i<12; i++)
        for( wd=0,day=1; day<=day_tab[leap][i]; day++)
        {
            date[i][wd][sw] = day;
            sw = ++sw%7;
            if(sw == 0)
                wd++;
        }

printf("\n==================The Calendar of Year %d=======================\n ",year);
for( i=0; i<6; i++)
{
    for(wd=0,k=0;k<7;k++)                   //将同一行的天数相加
        wd = wd + date[i][5][k] + date[i+6][5][k];
    wd=wd>0? 6:5;
    printf("%2d  %s  %2d  %s   \n",i+1,title,i+7,title);

    for(j=0;j<wd;j++)
    {
        printf("   ");
        for( k=0; k<7; k++)
            if(date[i][j][k])
                printf("%4d",date[i][j][k]);
            else printf("   ");
            printf("      ");
        for( k=0; k<7; k++)
            if(date[i+6][j][k])
                printf("%4d",date[i+6][j][k]);
            else printf("   ");
            printf(" \n");
    }
}

    puts("==================================================================");
    return 0;
}


/*计算该年份第一天是星期几*/
int firstday(int year)
{
    int leap(int ye);

    int i;
    long int n;

   
    n = year*365;

    for(i = 1; i < year; i++)
        if(leap(i))
            n += 1;   
    return (n%7);
}

int leap(int ye)
{
    if( (ye%4 ==0 && ye%100 != 0) || ye%400 ==0 )
        return 1;
    else
    return 0;
}


程序结果字符总是不对齐  哪边出错了呢

我写了一个，你试试看：
#include <stdlib.h>
#include <stdio.h>
int main()
{
 
  system("color c");
  
  int c, year, month, day, i, j, k ,diyitian;
 
  char ch;
  printf("sunyh1999 \n\n");
  printf("请输入今年的年份:");
  
  scanf("%d", &year);
  
  diyitian = ( year + ( year - 1 ) / 4 - ( year - 1) / 100 + ( year - 1 ) / 400 ) % 7;
  
  if (diyitian == 0)
   
 diyitian = 7;
  
  printf("  周一  周二  周三  周四  周五  周六  周七\n");
  
  if (year % 4 == 0)
   
 c = 29;
 
  else if (0 != year % 4)
  
    c = 28;
   
  for (month = 1; month <= 12; month++)
  {
    if (month == 1)
    {
      printf("                 ( %d月份)       \n", month);
      for (i = 1; i < diyitian; i++)
        printf("      ");
      for (day = 1; day <= 31; day++)
      {
        printf("%6d", day);
        if (i % 7 == 0)
        {
          printf("\n");
          k = i % 7 ;
          for (j = 1; j <= k; j++)
            printf("             ");
        }
        i++;
      }
      printf("\n");
    }
   
    else if (month == 2)
    {
      printf("                 ( %d月份)\n", month);
      k = i % 7 - 1;
      if (k ==  -1)
      {
        for (int i = 1; i <= 6; i++)
          printf("      ");
      }
      else
        for (j = 1; j <= k; j++)
          printf("      ");
      for (day = 1; day <= c; day++)
      {
        printf("%6d", day);
        if (i % 7 == 0)
        {
          printf("\n");
          k = i % 7;
          for (j = 1; j <= k; j++)
            printf("      ");
        }
        i++;
      }
      printf("\n");
    }
   
    else if (month == 3 || month == 5 || month == 7 || month == 8 || month ==10 || month == 12)
    {
      printf("                 ( %d月份)\n", month);
      k = i % 7 - 1;
      if (k ==  -1)
      {
        for (int i = 1; i <= 6; i++)
          printf("      ");
      }
      else
        for (j = 1; j <= k; j++)
          printf("      ");
      for (day = 1; day <= 31; day++)
      {
        printf("%6d", day);
        if (0 == i % 7 )
        {
          printf("\n");
          k = i % 7;
          for (j = 1; j <= k; j++)
            printf("      ");
        }
        i++;
      }
      printf("\n");
    }
    else if (month == 4 || month == 6 || month == 9 || month == 11)
    {
      printf("                 ( %d月份)\n", month);
      k = i % 7 - 1;
      if (k ==  -1)
      {
        for (int i = 1; i <= 6; i++)
          printf("      ");
      }
      else
        for (j = 1; j <= k; j++)
          printf("      ");
      for (day = 1; day <= 30; day++)
      {
        printf("%6d", day);
        if (i % 7 == 0)
        {
          printf("\n");
          k = i % 7;
          for (j = 1; j <= k; j++)
            printf("      ");
        }
        i++;
      }
      printf("\n");
    }
  }
  
  system("pause");
}

 

用户输入年份，打印年历

其实很简单，
    for(j=0;j<wd;j++)
    {
        printf("   ");
        for( k=0; k<7; k++)
            if(date[i][j][k])
                printf("%4d",date[i][j][k]);
            else printf("   ");
            printf("      ");
        for( k=0; k<7; k++)
            if(date[i+6][j][k])
                printf("%4d",date[i+6][j][k]);
            else printf("   ");
            printf(" \n");
    }
这段代码，有日期的时候%4d输出日期占4格，没有日期的地方你却只输出3个空格，当然对不齐了。

嗯，版主说的对，没有日期的地方你却只输出3个空格，当然对不齐了。

这下对了，真厉害！

不错，复制回去研究下

有几个地方修改一些可能会更好
bool isLeap(int year)
{
    return (year % 400 == 0) || year % 4 == 0 && year % 100 != 0); //如果是闰年返回1，否则返回0
}
int day[]= {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
day[1] += isLeap(year);//直接加上返回值就可获取2月的实际天数
这样可以减少很多判断语句。

只要修改一点点问题就能解决。