C语言反转字符串操作

#include <stdio.h>
void reverseString1(char *str)
{
  if (str == NULL)
    return;
  int begin = 0;
  int end = strlen(str) -1;
  while (begin < end)
  {
    char temp = str[begin];
    str[begin] = str[end];
    str[end] = temp;
    begin++;
    end--;
  }
}
void reverseString2(char *str)
{
  if (str == NULL)
    return;
  char *pBegin = str;
  char * pEnd = (char *)(str + strlen(str) - 1);
  while (pBegin < pEnd)
  {
    char  temp = *pBegin;
    *pBegin = *pEnd;
    *pEnd = temp;
    pBegin++;
    pEnd--;
  }
}
int main(void)
{
  char str[] = "abcdefghi";
  //reverseString1(str);
  reverseString2(str);
  printf("%s\n", str);
  system("pause");
  return 0;
}