My Window,Your Bridge!

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <string.h>
/****************************
 *
 * 模仿Linux 下的  cal命令
 * 
 * cal
 * 无参数显示当前月日历
 * -h      帮助信息
 * -m      指定月(1--12)
 * -y      指定年(>1900)
 * -j      显示本年的第几天，默认显示日期
 * -y,-m   缺省为当前年、月
 * 
 * for example:
 * 
 * $>cal -y 1997 -m 12
 * $>cal -y 1997
 * $>cal -m 12
 * $>cal -y 2008 -j
 * 
 * 
 * 操作系统对year的限制不同
 * Window  ：一般从1970~2038
 * Linux   : 基本没有限制
 * 
 * 
 * 
 * author:zhanglihai
 * date  : 2008/02/20
 * **************************/
//定义月的英文描述
char *month_name_en[12]={"January","February","March","April","May","June","July","August","September","October","November","December"};
char *week_name_en[7]={"Sun", "Mon", "Tue","Wed", "Thu", "Fri", "Sat"};
char *animals[12] = { "鼠", "牛", "虎", "兔",
                        "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪" };
int   month_max_day[12]={31,28,31,30,31,30,31,31,30,31,30,31};
typedef struct tm Date;
typedef struct tm *PDate;



void printHelp(){
        printf("\n模仿Linux 下的  cal命令"
                        "\n\n"
                        "cal\n"
                        "无参数显示当前月日历"
                        "\n\n"
                        "-h      帮助信息\n"
                        "-m      指定月(1--12)\n"
                        "-y      指定年(>1900)\n"
                        "-j      显示本年的第几天，默认显示日期\n"
                        "\n\n"
                        "-y,-m   缺省为当前年、月\n"
                        "\n"
                        "for example:\n"
                        "$>cal -y 1997 -m 12\n"
                        "$>cal -y 1997\n"
                        "$>cal -m 12\n"
                        "$>cal -y 2008 -j \n"
                        "\n"
                        "操作系统对year的限制不同\n"
                     "Window  ：一般从1970~2038\n"
                        "Linux   : 基本没有限制\n"
                        "\n\n"
                        "                                           author : zhanglihai\n"
                        "                                           date   : 2008/02/20\n");        
}


int monthMaxDay(int y,int m){
        int y1=y+1900;
        if(m==1)
        {
           if((y1%400==0)||(y1%4==0&&y1%100!=0))
             return 29;
        }        
        return month_max_day[m];
}

void printYearCal(PDate pdate,int fmt)
{
        int i,j,w,left;
        int m_len;
        int max_day1,max_day2;
        int day1,day2,gday1,gday2;
        int wday1,wday2;
        int year=pdate->tm_year;
        time_t _tm;
        PDate  _pdate;
                    pdate->tm_mon=0;
                    pdate->tm_mday=1;
                   _tm=mktime(pdate);
                 if(_tm==-1)
                 {
                   printf("can't   mktime . \n");
                   printf("-h    help info.\n");
                   return;        
                 }
        printf("\n%*d %s\n\n",(27*2-4*2-4)/2+10,pdate->tm_year+1900,animals[((pdate->tm_year+1900)-4)%12]);
                   _pdate=localtime(&_tm);
                   wday1=_pdate->tm_wday;
        day1=day2=gday1=gday2=1;
        for(i=0;i<12;i+=2)
        {
                    day1=day2=1;
                    max_day1=monthMaxDay(year,i);
         max_day2=monthMaxDay(year,i+1);
         wday2=(max_day1-(7-wday1))%7;
                //输出月英文名字
                m_len=strlen(month_name_en[i]);
                left=(27-m_len)/2+m_len;
                printf("%*s",left,month_name_en[i]);
                //剩下的位置用空格补齐
                for(j=0;j<27-left;j++)
                  printf(" ");
                //输出4个空格作为间隔
                for(j=0;j<4;j++)
                  printf(" ");
          //输出横排第二个月的名字          
           m_len=strlen(month_name_en[i+1]);
           left=(27-m_len)/2+m_len;
           printf("%*s\n",left,month_name_en[i+1]);
           
           //开始输出星期的英文名字
           printf("%s",week_name_en[0]);
           for(j=1;j<7;j++)
           {
                     printf("%4s",week_name_en[j]);
           }
           for(j=0;j<4;j++)
             printf(" ");
                      printf("%s",week_name_en[0]);
           for(j=1;j<7;j++)
           {
                     printf("%4s",week_name_en[j]);
           }
           printf("\n");  
           //星期的英文名字输出完毕
           //开始输出当前月的日期
           //一行一行的输出，同时输出两个月的
           //每个月的日期是一个6*7的方形矩阵 
           
           //先输出第一个行，

             if(i!=0){
               gday2=gday1+max_day1;
             }
             else
               gday2=1+max_day1;
             //输出站位空字符 
         for(w=0;w<wday1;w++)
         {
                   if(w==0)
                     printf("%3s"," ");
                   else
                     printf("%4s"," ");
         }
         //输出日期
         for(;w<7;w++)
         {
                 if(w==0){
                     printf("%3d",fmt?gday1:day1);
                  }
                  else{
                     printf("%4d",fmt?gday1:day1);
                   }
                   day1++;
                   gday1++;
         }
         //第一个月的第一行输出完毕
         //输出4个空格作为间隔
         printf("%4s"," ");
             //输出第二个月的第一行
             //此处应该可以根据上一个月算出从第几个开始
             
                   //输出站位空字符 
            for(w=0;w<wday2;w++)
         {
                   if(w==0)
                     printf("%3s"," ");
                   else
                     printf("%4s"," ");
         }  
             //输出日期

         for(;w<7;w++)
         {
                 if(w==0){
                     printf("%3d",fmt?gday2:day2);
                  }
                  else{
                     printf("%4d",fmt?gday2:day2);
                   }
                   day2++;
                   gday2++;
         }
           printf("\n");
           //开始下面的输出
           for(j=1;j<6;j++)
           {
                   //第一个矩阵
         //开始输出日期
          for(w=0;w<7;w++)
          {
                  if(day1<=max_day1)
                  {
                          if(w==0){
                             printf("%3d",fmt?gday1:day1);
                          }
                          else{
                             printf("%4d",fmt?gday1:day1);
                           }
                           day1++;
                           gday1++;
                  }else{
                           if(w==0)
                       printf("%3s"," ");
                       else
                       printf("%4s"," ");        
                  }
          }
             printf("%4s"," ");    
          
                //第二个矩阵 
              //gday2=gday1+max_day1;
          for(w=0;w<7;w++)
          {
                  if(day2<=max_day2)
                  {
                    if(w==0)
                      printf("%3d",fmt?gday2:day2);
                     else
                       printf("%4d",fmt?gday2:day2);
                           day2++;
                           gday2++;
                  }else{
                  
                           if(w==0)
                       printf("%3s"," ");
                       else
                       printf("%4s"," ");        
                  }
          }
          printf("\n");
           }
                   gday1=gday2;
                   wday1=(max_day1-(7-wday2)) % 7;
        }
        printf("\n");
}

void printMonthOnYearCal(PDate date,int fmt){
        int i;
        int m_len;
        int day;
        int max_day;
        int p=1;
        max_day=monthMaxDay(date->tm_year,date->tm_mon);
        printf("%*s %d %s\n",(27-(m_len=strlen(month_name_en[date->tm_mon])))/2+m_len-4,month_name_en[date->tm_mon],date->tm_year+1900,animals[((date->tm_year+1900)-4)%12]);
        printf(week_name_en[0]);
        for(i=1;i<7;i++)
        {
           printf("%*s",4,week_name_en[i]);        
        }
        printf("\n");
        for(i=0;i<date->tm_wday;i++)
        {
          if(i==0)
            printf("%*s",3," ");
          else
             printf("%*s",4," ");
        }
         day=1; 
         if(fmt==1)
            day=date->tm_yday+1;
        for(;i<7;i++){
                if(i==0)
              printf("%*d",3,day++);
            else
              printf("%*d",4,day++);
          if(i==6){
             i=-1; 
               printf("\n");
          }
          if(p++>=max_day)
            break;
        }
        printf("\n"); 
         
}
int main(int argc,char *argv[]){
        int y;
        int m;
        int fmt;
        fmt=0;
        y=-1;
        m=-1;
        time_t c_tm;
        time_t c_tm2;

        PDate pdate;
        PDate pdate2;
        int i;
        for(i=1;i<argc;)
        {
           if(!strcmp(argv[i],"-m")&&(i+1<argc))
           {
                     m=atoi(argv[i+1])-1;
                     if(m<0||m>11)
                     {
                                     printf("month  range (1~12)\n");
                                     printf("-h    help info.\n");
                                     exit(0);
                                     return 0;
                     }
                     i+=2;
           }        
           else if(!strcmp(argv[i],"-y") && (i+1<argc)){
                     y = atoi(argv[i+1])-1900;
                     if(y<=0)
                     {
                                     printf("year range (>1900)\n");
                                printf("-h    help info.\n");
                                     exit(0);
                                     return 0;
                     }
                     i+=2;
           }else if(!strcmp(argv[i],"-j"))
           {
                     i++;
                     fmt=1;
           }else if(!strcmp(argv[i],"-h"))
           {
                       printHelp();
                       exit(0);
                       return 0;
           }else {
                       printHelp();
                       exit(0);
                       return 0;
           }
        }
        time(&c_tm);
        pdate=localtime(&c_tm);
        if(m==-1)
        {
                if(y>0)
                {
                        pdate->tm_year=y;
                        printYearCal(pdate,fmt);                
                }else{
                          printMonthOnYearCal(pdate,fmt);
                }
        }else{
                if(y>0)
                {
                        pdate->tm_year=y;
                        pdate->tm_mon=m;
                        pdate->tm_mday=1;
                        c_tm2=mktime(pdate);
                        if(c_tm2==-1)
                         {
                           printf("can't mktime . \n");
                           printf("-h    help info.\n");
                            exit(0);
                            return 0;        
                         }
                        pdate2=localtime(&c_tm2);
                        printMonthOnYearCal(pdate2,fmt);                
                }else{
                           printMonthOnYearCal(pdate,fmt);
                }        
        }
  return 0;        
}