ex_5-5.c

   1 #include <string.h>
   2 #include <stdio.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 /*
  14
  15 Copy at most n chars of string source into string dest.
  16 Pad with '\0' if source has fewer chars than dest.
  17
  18 */
  19 char *ss_strncpy(char *dest, const char *source, int n)
  20 {
  21         char *d = dest;
  22         if(n >= 0 || n == '\0')
  23         {
  24                 while(--n >= 0 && (*dest++ = *source++) != '\0')
  25                         continue;
  26                 while(--n > 0)
  27                         *dest++ = '\0';
  28         }
  29
  30         return d;
  31 }
  32
  33 int main()
  34 {
  35         char source[] = { "Destination after..." };
  36         char dest[] = { "This is the destination before..." };
  37
  38         print_array(dest);
  39
  40         char *ans;
  41
  42         ans = strncpy(dest, source, 20);
  43
  44         printf("%p\n", ans);
  45         print_array(dest);
  46
  47         printf("\n\n");
  48
  49         char source2[] = { "Destination after..." };
  50         char dest2[] = { "This is the destination before..." };
  51
  52         print_array(dest2);
  53
  54         ss_strncpy(dest2, source2, 20);
  55
  56         printf("%p\n", ans);
  57         print_array(dest2);
  58         return 1;
  59 }