L-5 MCS 275 Fri 19 Jan 2001

/* MCS 275 L-5 Fri 19 Jan 2001 : pointers to process strings */

#include <stdio.h>
#include <stdlib.h>

#define  MAXLEN  80    /* maximum #characters in string */

int read_line (char s[]);
/* Reads a line of characters (until user hits enter).
   The string read is in "s" and the function returns the number
   "n" of characters in the string, i.e.: s[n] == '\0' */
int ptr_read_line (char *s);
/* This is the equivalent pointer version of the read_line,
   with the exception that there are no limits on the length. */

int main()
{
   char line[MAXLEN];
   char *ptr;
   int i,n;

   printf("Give a line (< %d characters) : ", MAXLEN);
   n = read_line(line);
   printf("Your line is :\n     \"%s\" \n", line);
   printf("There are %d characters on this line.\n", n);
   printf("Let us test the pointer version... \n");
   printf("Give a line (< %d characters) : ", MAXLEN);
   ptr = calloc(MAXLEN,sizeof(char));
   n = ptr_read_line(ptr);
   printf("Your line is :\n     \"%s\" \n", ptr);
   printf("There are %d characters on this line.\n", n);
   free(ptr);
   return 0;
}

int read_line (char s[])
{
  int c,i;
  for (i=0; (c=getchar()) != EOF && c != '\n' && i < MAXLEN; ++i)
     s[i] = c;
  s[i] = '\0';
  return i;
}

int ptr_read_line (char *s)
{
  int c,i;
  char *p;
  p = s;
  for (i=0; (c=getchar()) != EOF && c != '\n' && i < MAXLEN; ++i)
  {
     *p = c;
     ++p;
  }
  *p = '\0';
  return i;
}