ex_5-3.c

   1 #include <stdio.h>
   2 #include <string.h>
   3
   4 /* print contents of array */
   5 void print_array(char s[])
   6 {
   7         int i;
   8         for(i = 0; i < strlen(s); i++)
   9                 printf("%c", s[i]);
  10         printf("\n");
  11 }
  12
  13 /* previous version of strcat */
  14 void strcat_old(char s[], char t[])
  15 {
  16         int i, j;
  17         i = j = 0;
  18         while(s[i] != '\0')
  19                 i++;
  20         while((s[i++] = t[j++]) != '\0')
  21                 ;
  22 }
  23
  24 /* copy string of chars from t into s */
  25 void strcopy(char *s, char *t)
  26 {
  27         while(*s++ = *t++);
  28 }
  29
  30 /* pointer version of strcat - add string t to end of string s */
  31 void strcatptr(char *s, char *t)
  32 {
  33         while(*s) { ++s; } // find pointer val for end of string s
  34         strcopy(s,t);
  35 }
  36
  37 int main()
  38 {
  39         char buffer[128];
  40         char s[] = { "this is a string of chars " };
  41
  42         strcatptr(buffer,s);
  43         strcatptr(buffer,s);
  44
  45         print_array(buffer);
  46
  47         printf("\n");
  48
  49         return 1;
  50 }