ex_5-7.c

   1 #include <stdio.h>
   2 #include <string.h>
   3
   4 #define MAXLINES 1000  // max number of lines in buffer
   5 #define MAXLEN 1000    // max length of individual lines
   6
   7 // declare lines as an array of array of char
   8 // iow: create the maximum size empty buffer in global scope
   9 char lines[MAXLINES][MAXLEN];
  10
  11 /* print contents of array */
  12 void print_sparse_array(char s[][MAXLEN])
  13 {
  14         int i, j;
  15         for(i = 0; i < MAXLINES; i++)
  16         {
  17                 int found = 0;
  18                 for(j = 0; j < MAXLEN; j++)
  19                 {
  20                         if(s[i][j] != '\0') { found++; }
  21                 }
  22                 if(found > 0)
  23                 {
  24                         printf("%d:\t", i);
  25                         for(j = 0; j < MAXLEN; j++)
  26                                 printf("%c", s[i][j]);
  27                         printf("\n");
  28                 }
  29         }
  30         printf("\n");
  31 }
  32
  33 /* From K&R Page 29 */
  34 int getline(char s[], int lim)
  35 {
  36         int c, i;
  37         for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; i++)
  38                 s[i] = c;
  39         if (c == '\n')
  40                 s[i++] = c;
  41         s[i] = '\0';
  42         return i;
  43 }
  44
  45
  46 /*
  47
  48 reads input lines from stdin and stores each line in buffer named lines
  49
  50 */
  51 int readlines(char lines[][MAXLEN], int maxlines)
  52 {
  53         int len, nlines = 0;
  54
  55         while((len = getline(lines[nlines], MAXLEN)) > 0)
  56                 if(nlines >= maxlines) // when buffer full, return
  57                         return -1;
  58                 else
  59                         lines[nlines++][len - 1] = '\0'; // delete newline
  60         return nlines;
  61 }
  62
  63 int main()
  64 {
  65         int length = readlines(lines, MAXLINES);
  66         printf("Number of Lines Stored: %d\n", length);
  67         print_sparse_array(lines);
  68         return 1;
  69 }