replace function

How do you use the replace function to change a string.

Thanks for the correction. My question relates to writing a function that copies the contents of a string and then replaces it in reverse order. I am not fully aware of all the functions in C, so based on what I was able to find out, I thought there might be one.
Here is my code:
Any help would be appreciated!

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

void strcopy(char string1[], char string2[])
{
int i =0;
int length;

while ( string2[i] !='\0')

{
string1[i] = string2[i];
++i
}
string1[i] = '\o'

length = strlen( string1 );

while (string1[i] !='\o')

{
string2[i] = string1[length]
++i
--length
}
while (string2[length] !='\o')
return,

>My question relates to writing a function that copies the
>contents of a string and then replaces it in reverse order.
So you want to copy a string, reverse it, and then replace the original string with the reversed copy? That's too much work for a simple operation, this should have the same result in a more efficient manner:

Code:

---

void reverse ( char *s )
{
  int t, i, j;
  size_t len = strlen ( s ) - 1;
  for ( i = 0, j = len; i < j; i++, j-- )
    t = s[i], s[i] = s[j], s[j] = t;
}

---

-Prelude