使用指针反向字符串

Question

I'm trying to reverse a string using pointers.When i try to print the reversed string instead of getting DCBA i'm getting out only as BA?Can anyone help me on this?

#include<stdio.h>
void reverse(char *);
void main()
{
  char str[5] = "ABCD";
  reverse(str);
}

void reverse(char *str)
{
  char *rev_str = str;
  char temp;
  while(*str)
      str++;
  --str;

  while(rev_str < str)
  {
      temp = *rev_str;
      *rev_str = *str;
      *str = temp;   
      rev_str++;      
      str--;
  }
  printf("reversed string is %s",str);
}

Answer 1

You're losing your pointer to the beginning of the string, so when you print it out you're not starting from the first character, because str no longer points to the first character. Just put in a placeholder variable to keep a pointer to the beginning of the string.

void reverse(char *str)
{
  char *begin = str; /* Keeps a pointer to the beginning of str */
  char *rev_str = str;
  char temp;
  while(*str)
      str++;
  --str;

  while(rev_str < str)
  {
      temp = *rev_str;
      *rev_str = *str;
      *str = temp;   
      rev_str++;      
      str--;
  }
  printf("reversed string is %s\n", begin);
}

Answer 2

char* strrev(chr* src)
{      
       char* dest
       int len=0, index=0 , rindex=0;

       while(*(src+len) != '\0')
       { len++ }

       rindex=len-1;

       while(rindex > =0)
       {
           *(dest+index) = *(src + rindex)
            index++;
            rindex--;
       }

      *(dest+index) = '\0';


return dest;
}