@programminginc - страница 1750

What is the use of double pointers or ** Why we will use it in our program can anyone gave me a simple example My book examples are somewhat tricky My teacher only said that it is a pointer which is pointing to another pointer or holding address of any other pointer

Dima

What is the use of double pointers or ** Why we will use it in our program can anyone gave me a simple example My book examples are somewhat tricky My teacher only said that it is a pointer which is pointing to another pointer or holding address of any other pointer

She’s right

Anonymous

She’s right

What? 😒😒😏😏😏 I asked something Regarding ** Of c language So can you tell me admin

Mat

What? 😒😒😏😏😏 I asked something Regarding ** Of c language So can you tell me admin

Your teacher is right

Anonymous

Your teacher is right

But I couldn't get what it actually meant A pointer is holding address of another pointer 🤔🤔🤔🤔 Why I will use it

Mat

Usually they're used to create array of arrays, or a matrix

Anonymous

Usually they're used to create array of arrays, or a matrix

Can you give one simple example

Suresh

Can you give one simple example

+1

Mat

Can you give one simple example

int mat[2][3]; Do you know what this is?

Anonymous

int mat[2][3]; Do you know what this is?

Yes it is 2d array

Anonymous

I have studied about it in computer science and maths

Suresh

Only used for accessing multi dimensional array or matrix?

Suresh

Anyother use case

Anonymous

int mat[2][3]; Do you know what this is?

So where we have used here **

Mat

You can write it as int **mat; mat = malloc(sizeof(int*)*2); for(int i = 0; i < 2; i++) { mat[i] = malloc(sizeof(int)*3); }

Anonymous

If I've const char a[][] = {"fir","sec","thi"}; How to point to a?

Anonymous

This array is incorrect

Anonymous

why?

Anonymous

This array is incorrect

If the no of columns are 3 and rows are filled as 1 Then @superrealusername

Anonymous

This array is incorrect

which one?

Anonymous

Are you blind?

Anonymous

Are you blind?

kindly reply to some comment.

Anonymous

You initialized your 2d array wrong way, completely.

Mat

Are you blind?

Point to the error and offer at least a tip to the correction

Anonymous

This array is incorrect

I mean const char a[3][1]= {"first", "second", "third" };

Anonymous

You can write it as int **mat; mat = malloc(sizeof(int*)*2); for(int i = 0; i < 2; i++) { mat[i] = malloc(sizeof(int)*3); }

@Mayaletitgo do you know what mat[i] = malloc(...) means here? what does it do?

Anonymous

We are talking about his mistake

Anonymous

Is it the column size or the row size that we can skip while declaration?

Anonymous

@Mayaletitgo do you know what mat[i] = malloc(...) means here? what does it do?

Well my school textbook have never used this complex function malloc() My teacher said that I can explain you but you will learn about it in university 😁😁😁😄😁😆 May be you cannot understand

Anonymous

Is it the column size or the row size that we can skip while declaration?

Oh 😁😁😁😁 We can never skip both row or coloum size Only one either row or coloumn

Anonymous

What is mat[i]?

Anonymous

I'am asking which one and not both.

Anonymous

Is it some integer or what?

Anonymous

okk

Anonymous

What is mat[i]?

It's a 1d array

Anonymous

I mean const char a[3][1]= {"first", "second", "third" };

Reply me if I was correct here or not Michel

Anonymous

First of all it's a pointer to pointer.

Anonymous

First of all it's a pointer to pointer.

Mat[i] Is a single pointer

Anonymous

How is it double

Anonymous

Really?

Anonymous

You can write it as int **mat; mat = malloc(sizeof(int*)*2); for(int i = 0; i < 2; i++) { mat[i] = malloc(sizeof(int)*3); }

^

Anonymous

You can write it as int **mat; mat = malloc(sizeof(int*)*2); for(int i = 0; i < 2; i++) { mat[i] = malloc(sizeof(int)*3); }

Sorry I know nothing about malloc as I have never read about it So cannot say anything about it It seems tough concept for high school guy

Anonymous

^

Yes here **mat is a double pointer it was pointing to other pointer

Mat

Sorry I know nothing about malloc as I have never read about it So cannot say anything about it It seems tough concept for high school guy

It's a pretty stupid concept that you can search online :) It's funny how you didn't even try yo understand my code before starting with other questions

Anonymous

It's a pretty stupid concept that you can search online :) It's funny how you didn't even try yo understand my code before starting with other questions

Ok but I understand you admin actually it(malloc) was not in our syllabus/curriculum and I already have big assignments to complete recently (yesterday )she send a big assignment of 28 questions of pointers That's why I asked about ** Because it's very different Thanks for your help admin