Reverse array of characters

Code:

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

void reverseAr(char ar[], int n);

int main()
{
 int choice;
 char *abc= ar[];

switch (choice) {
 case 1:
        reverseAr(ar);
    break;

void reverseAr(char ar[], int n)
{
    char c;
    char *p, *q;
 
    p = ar;
    if (!p)
        return;
 
    q = p + 1;
    if (*q == '\0')
        return;
 
    c = *p;
    reverseAr(ar[]);
 
    while (*q != '\0') {
        *p = *q;
        p++;
        q++;
    }
    *p = c;
 
    return;

}

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My codes keep couldn't get the reverse array of characters. Do anyone mind to tell me where is my mistake? Thank you in advance.

This looks wrong:

Code:

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char *abc= ar[];

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You probably want to declare ar, and maybe initialise it at the same time, e.g.,

Code:

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char ar[] = "hello";

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This is wrong:
reverseAr(ar);
You declared reverseAr with two parameters, but you only passed it one argument when calling it.

I suggest that you get rid of the choice variable and the switch. You might need it later, but for now it is just a distraction. As you do so, you also need to fix your main function such that it is properly defined (watch out for the closing brace).

This is wrong:

Code:

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reverseAr(ar[]);

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You probably want to call reverseAr, but whereas you passed ar correctly earlier, this time you do so wrongly, and you're still missing the second argument. In fact, since you have a loop later, I guess that this recursive call should be removed... but whether to do this or not depends on what is the algorithm that you have in mind.

This code seems needlessly complicated. As laserlight pointed out there seems to be an odd mix of recursion and iteration. If you want to do it recursively stick to recursion and don't have the unrequired iterative loop (the recursive solution, by the way, will be an example of tail recursion which is easily converted to an iterative solution). I suggest that doing the recursive version first, and then converting this solution to an iterative solution might be valuable for learning.

To help with the recursive solution, answering these questions may help...

* If the string length is 1, how would this be reversed?
* If the string length is 2, how would this be reversed?

Another question:

* If you want to swap the first character in a string with the final character in a string, how would you do this?

I couldn't initialize the array as I have to get the array of characters from user input, hence I do not know how to do so.

Code:

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void reverseAr(char ar[], int n)
{       
  int i=0,j;
  char temp;
 
  int len = strlen(ar);
  if (n==0 || n==1)
      return;
  else
  {


temp=*ar;
  *ar=ar[n-1];
  ar[n-1]=temp;
  }
  return reverseAr(ar+1,n-2);
}

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This is continued in Reverse array of characters using recursive function.

*thread closed*