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Free calling different results from malloc

The following is a C program written to print a different combination of characters in a string.

This is not an efficient way, as this algorithm creates many extra lines. However, my question is NOT about how to solve this problem more efficiently.

The program works (albeit inefficiently) and prints a different combination of line characters (correctly). But when I try to freecreate additional lines that arise, I run into a problem. freethat causes the problem is at the end of the thr function recur_printc(it is commented out).

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

#define N 3

void recur_printc(char *, int, char *);
int main()
{
    char str[] = "abc";
    char *print_arr = malloc(N * sizeof(char));
    //Call recur_print
    recur_printc(print_arr, 0, str);
    free(print_arr);
    return 0;
}

void recur_printc( char *print_arr, int index, char *remaining)
{
    int i, j, rem_len, index_4_next;
    //base case, only last cahracter remaining
    if(strlen(remaining) == 1)
    {
        print_arr[index] = remaining[0];
        //Print the print_arr
        for(i=0; i<N; i++)
        {
            printf("%c",print_arr[i]);
        }
        printf("\n");
        return;
    }
    //If more than one character remaining
    else
    {
        rem_len = strlen(remaining);
        for(i=0; i<rem_len; i++)
        {
            //Add one character to print_arr
            print_arr[index] = remaining[i];
            //now create the string with remaining characters 
            char *remaining_for_next = malloc((rem_len-1) * sizeof(char));
            index_4_next = 0;
            for(j=0; j<rem_len; j++)
            {
                if(j != i)
                {
                    remaining_for_next[index_4_next] = remaining[j];
                    index_4_next++;
                }
            }
            //call recur_print 
            recur_printc(print_arr, index+1, remaining_for_next);
            //Free the remainin_for_next
            /*------This is causing issues----*/
            //free(remaining_for_next);
            remaining_for_next = NULL;
        }
    }
}

When I ran this program in gdb, I noticed that when i=1for the first instance recur_print, malloca strange thing happens with .

When this line is completed:

char *remaining_for_next = malloc((rem_len-1) * sizeof(char));

rem_len-1 2, malloc 3 , , - strlen ( 3 2). , . ( , free().)

gdb:

42              char *remaining_for_next = malloc((rem_len-1) * sizeof(char));
(gdb) print remaining_for_next
$3 = 0x0
(gdb) n
43              index_4_next = 0;
(gdb) print remaining_for_next
$4 = 0x602030 "@ `"
(gdb) print rem_len-1
$5 = 2
(gdb) q

. , , comibnation ( ) . , , remaining_for_next (, malloc ).

+4
2

, , , .

, :

for(j=0; j<rem_len; j++) {
  if(j != i) {
    remaining_for_next[index_4_next] = remaining[j];
    index_4_next++;
  }
}

:

for(j=0; j<rem_len; j++) {
  if(j != i) {
    remaining_for_next[index_4_next] = remaining[j];
    index_4_next++;
  }
}
remaining_for_next[index_4_next] = '\0';

:

gsamaras@gsamaras:~/Desktop/px$ gcc -Wall main.c
gsamaras@gsamaras:~/Desktop/px$ ./a.out 
abc
acb
bac
bca
cab
cba

. , !

:

, :

char *remaining_for_next = malloc((rem_len - 1) * sizeof(char));

:

char *remaining_for_next = malloc((rem_len) * sizeof(char));

.

, +1. >

+1

​​, , remaining_for_next . strlen(), , , . . , , recur_printc , , . remaining_for_next , .

+2
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