I am unable to retrieve the updated values in main function

Question

//Generating all possible binary strings of lenght 'n' 
#include<stdio.h>
#include<stdlib.h>
char a[20];
int ind = 0;
void generateAllBinaryStrings(int n, char **arr,int `i){
 if (i == n){
    printf("%s  \n",a);
    arr[ind] = a;
    ind++;
    return ;
} 

a[i] = '0';
generateAllBinaryStrings(n, arr, i+1); 

a[i] = '1';
generateAllBinaryStrings(n, arr, i+1) ; 

 }

int main(){
 int n = 3,k;   
 char *arr[8];
 generateAllBinaryStrings(n, arr, 0);
 printf("\n");
 for(k=0;k<8;k++)
    printf("%s\n",arr[k]);
return 0;
}

// Why this code giving weird output? //How to return the array of pointers values updated in another function to main()???

//What's wrong with this code?

//output:

cherrycharan@cherrycharan-HP-Notebook:~/Desktop$ ./a.out
 // In generateAllBinaryStrings()
 000  
 001   
 010  
 011  
 100  
 101  
 110  
 111  

 // In main()
 111
 111
 111
 111
 111
 111
 111
 111

// Why this code is giving weird output? //How to return the array of pointers values updated in another function to main()???

//What's wrong with this code?

The question is rather what you are trying to do and where you allocate memory for the strings. The code posted doesn't make sense on it's own. — Lundin, Jun 10 '19 at 08:29

score 1 · Answer 1 · answered Jun 10 '19 at 08:17

1

Since you are doing pointer assignment, pointers in arr will be always pointing to updated contents of a that is 111.

arr[ind] = a;

Copy the contents instead.

arr[ind] = strdup(a);

And make sure you free afterwards.

answered Jun 10 '19 at 08:17

kiran Biradar

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Tq very much. I have got proper output now. – cherry charan Jun 10 '19 at 08:30
2

So you should mark this answer as such. ;-) – the busybee Jun 10 '19 at 09:27
Rather, if this was the problem, this is just one of endless duplicates where the OP tries to "store data into pointers". Close vote to the linked canonical dupe instead of answering. – Lundin Jun 10 '19 at 14:05
@Lundin I agree you can duplicates, not only for this question but for all the new questions at this stage of Stack overflow. – kiran Biradar Jun 10 '19 at 14:07

I am unable to retrieve the updated values in main function

1 Answers1