program12_02.c

来自「[C语言入门经典(第4版)]整本书的源码！值得推荐！全部是最简单的源码！」· C语言 代码 · 共 69 行

/* Program 12.2  As the saying goes...it comes back! */
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

const int LENGTH = 80;                 /* Maximum input length */

int main(void)
{
  char *proverbs[] =
             {  "Many a mickle makes a muckle.\n",
                "Too many cooks spoil the broth.\n",
                "He who laughs last didn't get the joke in"
                                       " the first place.\n"
             };

  char more[LENGTH];                   /* Stores a new proverb */
  FILE *pfile = NULL;                  /* File pointer         */
  char *filename = "C:\\myfile.txt";

  /* Create a new file( if myfile.txt does not exist */
  if(!(pfile = fopen(filename, "w")))    /* Open the file to write it */
  {
    printf("Error opening %s for writing. Program terminated.", filename);
    exit(1);
  }

  /* Write our first three sayings to the file. */
  int count = sizeof proverbs/sizeof proverbs[0];
  for(int i = 0 ; i < count ; i++)
    fputs(proverbs[i], pfile);

  fclose(pfile);                       /* Close the file */

  /* Open the file to append more proverbs */
  if(!(pfile = fopen(filename, "a")))
  {
    printf("Error opening %s for writing. Program terminated.", filename);
    exit(1);
  }

  printf("Enter proverbs of less than 80 characters or press Enter to end:\n");
  while(true)
  {
    fgets(more, LENGTH, stdin);          /* Read a proverb           */
    if(more[0] == '\n')                  /* If its empty line        */
      break;                             /* end input operation      */
    fputs(more, pfile);                  /* Write the new proverb    */
  }

  fclose(pfile);                         /* Close the file           */

  if(!(pfile = fopen(filename, "r")))    /* Open the file to read it */
  {
    printf("Error opening %s for writing. Program terminated.", filename);
    exit(1);
  }

  /* Read and output the file contents */
  printf("The proverbs in the file are:\n\n");
  while(fgets(more, LENGTH, pfile))      /* Read a proverb */
   printf("%s", more);                   /* and display it */

  fclose(pfile);                         /* Close the file */
  remove(filename);                      /* and remove it  */
  return 0;
}