厦大小学期C语言程序设计实践（二）

唐伯虎

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　　所有实践项目的源程序可到我的Github上下载：https://github.com/liulizhi1996/C-Programming-Practice-in-short-semester
　　任务一：颠倒的世界
　　小明最近突然喜欢倒着写字，写出来的句子全是颠倒的，也就是把一句话里的字符全都逆序写，譬如“I Love This Game！”，他就偏偏要写成“!emaG sihT evoL I”弄的小华同他Email交流都很难受。请你帮助小华解决这个问题，将输入的字符串全都还原成本来的面目。
　　任务1要求：
　　利用main函数带参数的功能，编写程序，将命令行中的字符串全部逆序显示出来。例如编写的可执行文件为go.exe 那么运行 go !emaG sihT evoL I 时，显示出I Love This Game！

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char **argv)
{
  if (argc <= 1)
  {
    perror("usage: ./reverse.out [string]\n");
  }
  int len;
  for (int i = argc-1; i > 0; --i)
  {
  len = (int)strlen(argv[i]);
  for (int j = len-1; j >= 0; --j)
  printf("%c", argv[i][j]);
  printf(" ");
  }
  printf("\n");
  return 0;
}

　　任务二：时间转换
　　由于工作原因，小明常常需要签署文件日期，但他比较偷懒，都用阿拉伯数字签署，譬如3.8表示三月八日，7.12表示七月十二日。最近公司改组成外资企业，主管要求将所有的日期全部更改为英文表示，一来同国际接轨，二来也不容易篡改，譬如将3.8表示为March the eighth 面对这么多的日期，小明犯愁了，他英文不好，那么多的英文单词他记不住。而且小明还是个马大哈，有时候居然会签出3.32（三月三十二日）这样的日期，为了避免被上司责备，趁着这次机会也赶快一并修改。请你帮助小明完成这个任务。
　　任务2要求：
　　利用main函数带参数的功能，编写程序，将命令行中的字符串翻译成英文表示，每行显示一个日期，同时需检查日期表示是否有误，如有误，请给出提示。例如：编写的可执行文件为go.exe 那么运行go 3.8  5.5  4.38 时显示
　　March the eighth
　　May the fifth
　　Error

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int days[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
char english_months[][15] = {"", "January", "February", "March", "April", "May", "June", 
               "July", "August", "September", "October", "November", "December"};
char english_days[][15] = {"", "first", "second", "third", "fourth", "fifth", "sixth", "seventh", 
   "eighth", "ninth", "tenth", "eleventh", "twelfth", "thirteenth", 
   "fourteenth", "fifteenth", "sixteenth", "seventeenth", "eighteenth", 
   "nineteenth", "twentieth", "twenty-first", "twenty-second", "twenty-third", 
   "twenty-fourth","twenty-fifth", "twenty-sixth", "twenty-seventh",
   "twenty-eighth", "twenty-ninth", "thirtieth", "thirty-first"};
int main(int argc, char **argv)
{
  if (argc <= 1)
  {
    perror("usage: ./date.out [date]\n");
  }
  int month, day, is_legal, j;
  for (int i = 1; i < argc; ++i)
  {
    is_legal = 1;
  month = 0;
    for (j = 0; argv[i][j] && argv[i][j] != '.'; ++j)
    {
      if ('0' <= argv[i][j] && argv[i][j] <= '9')
        month = month * 10 + (argv[i][j] - '0');
      else
      {
        is_legal = 0;
        break;
      }
    }
    if (!is_legal)
    {
      printf("Error\n");
      continue;
    }
    day = 0;
    for (j++; argv[i][j]; ++j)
    {
      if ('0' <= argv[i][j] && argv[i][j] <= '9')
        day = day * 10 + (argv[i][j] - '0');
      else
      {
        is_legal = 0;
        break;
      }
    }
    if (!is_legal)
    {
      printf("Error\n");
      continue;
    }
    if (1 <= month && month <= 12)
    {
      if (1 <= day && day <= days[month])
        printf("%s the %s\n", english_months[month], english_days[day]);
      else
      {
        printf("Error\n");
        continue;
      }
    }
    else
    {
      printf("Error\n");
      continue;
    }
  }
  return 0;
}

　　任务三：时间转换(续)
　　小明觉得这么一点点的手工输入还是有点麻烦，他把需要翻译的日期都整理到文本文件in.txt中，请你帮助小明，将其中的内容翻译完毕后保存到文本文件out.txt中，便于他统一处理。
　　任务3要求：翻译过程同任务2，将结果保存至文件out.txt中

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int days[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
char english_months[][15] = {"", "January", "February", "March", "April", "May", "June", 
               "July", "August", "September", "October", "November", "December"};
char english_days[][15] = {"", "first", "second", "third", "fourth", "fifth", "sixth", "seventh", 
               "eighth", "ninth", "tenth", "eleventh", "twelfth", "thirteenth", 
               "fourteenth", "fifteenth", "sixteenth", "seventeenth", "eighteenth", 
               "nineteenth", "twentieth", "twenty-first", "twenty-second", "twenty-third", 
               "twenty-fourth","twenty-fifth", "twenty-sixth", "twenty-seventh",
               "twenty-eighth", "twenty-ninth", "thirtieth", "thirty-first"};
int main(int argc, char **argv)
{
  if (argc <= 1)
  {
    perror("usage: ./datefile.out [date]\n");
  }
  FILE *fp_in = fopen("in.txt", "w");
  FILE *fp_out = fopen("out.txt", "w");
  int month, day, is_legal, j;
  for (int i = 1; i < argc; ++i)
  {
    fprintf(fp_in, "%s\n", argv[i]);
    is_legal = 1;
  month = 0;
    for (j = 0; argv[i][j] && argv[i][j] != '.'; ++j)
    {
      if ('0' <= argv[i][j] && argv[i][j] <= '9')
        month = month * 10 + (argv[i][j] - '0');
      else
      {
        is_legal = 0;
        break;
      }
    }
    if (!is_legal)
    {
      fprintf(fp_out, "Error\n");
      continue;
    }
    day = 0;
    for (j++; argv[i][j]; ++j)
    {
      if ('0' <= argv[i][j] && argv[i][j] <= '9')
        day = day * 10 + (argv[i][j] - '0');
      else
      {
        is_legal = 0;
        break;
      }
    }
    if (!is_legal)
    {
      fprintf(fp_out, "Error\n");
      continue;
    }
    if (1 <= month && month <= 12)
    {
      if (1 <= day && day <= days[month])
        fprintf(fp_out, "%s the %s\n", english_months[month], english_days[day]);
      else
      {
        fprintf(fp_out, "Error\n");
        continue;
      }
    }
    else
    {
      fprintf(fp_out, "Error\n");
      continue;
    }
  }
  fclose(fp_in);
  fclose(fp_out);
  return 0;
}

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