Reversing a string in c with recursion

Question

I have written code to reverse a string in c... it works fine but I can\'t return the reversed string in the main() function.

#include

        

Answer 1

#include <stdio.h>
#define MAX 100
int main()
{
char str[MAX], *rev;
scanf("%s", str);
rev = reverse(str); 
printf("The reversed string is : %s\n", rev);
return 0;
}
char *reverse(char ch[])
   {
    static char r[MAX];
    static int i=0;
    if(*ch == '\0') return "";
    else 
   {
    reverse(ch+1);
    r[i++]=*ch;
   }
    return r;
   }

Answer 2

You need to modify the string, i.e. the input buffer to reverse(), instead of just printing it.

Doing this recursively seems a bit obnoxious, but should of course be possible.

Basically, I guess the printing becomes an assignment, something like this:

1. Base: The reversal of an empty string is the empty string.
2. Step: The reversal of a string begins by swapping the first and last characters, then recursing over the remainder of the string.

Answer 3

#include <iostream>
using namespace std;

reverse( char *str)
{
    if (*str!='\0')
    {
       reverse(str+1);
       cout<<*str;
    }
//cout<<*str   when i am just printing here then why this is printing after one space ??
}

int main()
{   
    string a ;  
    cin>>a;   
    reverse(&a[0]); 
    return 0;
}

Answer 4

Following is one way to reverse string using recursion!

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

void rev_str_recursive(char arr[], size_t iStart, size_t iLast)
{
    if( iStart < iLast )
    {
        //swap
        char temp = arr[iStart];
        arr[iStart] = arr[iLast];
        arr[iLast] = temp;

        rev_str_recursive(arr, ++iStart, --iLast);  
    }
}

void main()
{
    char cArray[] = {"A quick brown fox jumps over a lazy dog"};

    rev_str_recursive(cArray, 0, strlen(cArray)-1);
}

Answer 5

Here is another way to reverse a string using recursion:

void reverseString(char* dest, char *src, int len) {
    if (src == NULL || len == 0)
        return;

    reverseString(dest, src + 1, len - 1);
    strncat_s(dest, len + 1, src, 1);
}

You can call like that:

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

#define STRING "Let's try this one."
#define SIZE 20

void main() {

    char* src = (char*)malloc(SIZE);
    char* dest = (char*)malloc(SIZE);

    strcpy_s(dest, SIZE, "");
    strcpy_s(src, SIZE, STRING);

    reverseString(dest, src, strlen(src));
    /* Do anything with dest. */
    // printf("%s\n", dest);

    free(src);
    free(dest);
}

Answer 6

use sprintf it will print your reversed string into buffer.

#include<stdio.h>

char *b;

main()
{
  char a[17]="abcdefg";
  char buffer[17];
  buffer[0]= '\0';
  b = buffer;
  reverse(a);
  printf("%s\n",buffer);
}
int reverse(char *a)
{
   if(*a!='\0')
   {   
     reverse(a+1);
     sprintf(b,"%c",*a);
     b++;
   }

}