revise answer

Added a check for NULL pointers and did other minor tweaks.

Author: fsaadatmand

chapter05/5-3.c

@@ -1,6 +1,7 @@
 /*
  * Exercise 5-3. Write a pointer version of the function strcat that we showed
  * in Chapter 2: strcat(s,t) copies the string t to the end of s.
+ *
  * By Faisal Saadatmand
  */
 
@@ -12,18 +13,19 @@ void strCat(char *, char *);
 /* concatenate t to end of s; s must be big enough */
 void strCat(char *s, char *t)
 {
-  while (*s)             /* find end of s */
+  while (s && *s) /* find end of s */
 	  ++s;
-  while ((*s++ = *t++))  /* copy t */
+  while (s && t && (*s++ = *t++)) /* copy t */
     ;
 }
 
 int main(void)
 {
-  char string1[64] = { "test this " };
-  char string2[] = { "function" };
+	char str1[64] = { "conca" };
+	char str2[] = { "tonate" };
 
-  strCat(string1, string2);
-  printf("%s\n", string1);
-  return 0;
+	strCat(str1, str2);
+	printf("%s\n", str1);
+
+	return 0;
 }