Thread: Problem with my string reverse code

Hi all, I was just playing around with strings, and I tried doing a string reverse using pointers, however, it did not turn out as I wanted. I tried using arrays and it works, but I cant do the same for pointers. As I'm still quite new to pointers, please guide me. Thank you. The code is as below:

Code:

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

char * reverseString(char *);

int main()
{
   char *input, *p;
   
   input = malloc(100);
   fgets(input, 100, stdin);
   if((p=strchr(input, '\n'))!=NULL)
      *p = '\0';
	
   printf("%s\n", reverseString(input));
   
   return 0;	
}

char * reverseString(char *originalString)
{
   char *temp;
   int length = 0;
   
   length = strlen(originalString);
   temp = malloc(length);
   
   temp = ???; /* I should assign temp to point somewhere? */
   
   /* assign pointer to point at end of string */
   originalString = &(originalString[length-1]);
   
   while(length)
   {
      *temp++ = *originalString--;
      length--;
   }

   return temp;
}

it's been a while since I've reversed strings in the file the following code should work

Code:

 
// CH reads char from the file 
// i is the offset of the file u r reading from ( end of the file) 
// size is the offset i multiplied by -1 
// *f2 is the file pointer we save the reversed string 
// *f1 is the file pointer we read the string from 
int Recursion( char CH , long i ,long SiZe, FILE *f2 , FILE *f1)
{
  fputc(CH , f2); // Puts it in a new file
// printf("%c" , CH);
  if ( i == SiZe   )
  return 0;
  
  i--;
  fseek(f1 , i , SEEK_END)  ;
  CH = fgetc(f1);
  printf("%c" , CH);
  Recursion( CH , i , SiZe ,f2 , f1);
}

// I'm not sure if the if statement is right c if it works it may print some spaces :P //

Hope this makes things clearer for ya

Thx hk_mp5kpdw! I tried assigning another char pointer to temp, and took into account of the NULL character, now it works perfectly. Thx again!

Thx Bella_Rosa for the reply, will try your method too!