Initialize 2D Array with characters c++

Question

I am trying to initialize a 2D array to create a map that will print out stars at the beginning of the program. I have my initialization in a function. Whenever I try to run the program, I get crazy numbers. Any tips on how to make this 2D array correct? This is my code and the result that I get:

void InitializeArray()
{
char map[Y_DIM][X_DIM];

for (int row = 0; row < Y_DIM; row++)
{
   for (int col = 0; col < X_DIM; col++)
   {
      cout << map[row][col];
      cout << "*";
   }
cout << endl;
}
}

This is my result

`*2*.*v*/***************
******************
?*?*?*u*/****?*?*?*?*?*?*?*?*?*!*`**
****?*!*`******?*!*`******
?*-*?**?****U*?*7*v*/****?**@**
****?*?*7*v*/*****E*]*v*/****
?*!*`*******-*?**?****?*!*`**
****?**@******p*    *@******
?*-*?**?****************
****?*?*7*v*/****p* *@******

'I am trying to initialize a 2D array'. I don't see your initialization. — cbel
– cbel, Commented Apr 3, 2014 at 0:43

Mud · Accepted Answer · 2014-04-03 00:37:59Z

3

That is not initializing the array, it's printing it. Given that it's not initialized, it prints garbage.

Instead of:

 cout << map[row][col];

you want:

map[row][col] = '*';

That will set the initial value for each cell in your array, which is to say, initialize it.

You can also do this at the same time you define the array using C++'s array initializer syntax, but your approach is better.

edited Apr 3, 2014 at 0:37

answered Apr 3, 2014 at 0:32

Mud

29.2k12 gold badges64 silver badges100 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

savannaalexis Over a year ago

I need to initialize and then print it. How would I initialize?

πάντα ῥεῖ Over a year ago

@savannaalexis 'How would I initialize?' He just wrote this in his answer: map[row][col] = '*';!!

David Merinos · Accepted Answer · 2014-04-03 00:49:26Z

0

What I'd do:

#include <iostream>
using namespace std;
const int Y_DIM = 8;
const int X_DIM = 9;
void initializeArray() {
    char map[Y_DIM][X_DIM]={'*'};
    for (int row = 0; row < Y_DIM; row++)
    {
        for (int col = 0; col < X_DIM; col++)
        {
            map[row][col]='*';
            cout << map[row][col];
        }
    cout << "\n";   
}
}
int main() {
    initializeArray();
    return 0;
}

Output

*********
*********
*********
*********
*********
*********
*********
*********

Try it on ideone.com

answered Apr 3, 2014 at 0:49

David Merinos

1,2971 gold badge14 silver badges41 bronze badges

5 Comments

πάντα ῥεῖ Over a year ago

={'*'}; is redundant.

David Merinos Over a year ago

@πάνταῥεῖ Just making sure it get's allocated. Once I made string str; and then got some garbage when I tried to see what it contained. Then changed to string str = ""; and all was back to normal :)

Mud Over a year ago

In this case, it will cause the first element of map to be initialized to '*' and all subsequent elements to get 0. You then overwrite those values in the loop, so πάντα ῥεῖ is right: it's redundant.

M.M Over a year ago

@David, if that string story is true then you had some other memory corruption in your program that happened to be overflowing and reading the memory of your string

David Merinos Over a year ago

@MattMcNabb It is true, I've been initializing all my variables since then. D:

Collectives™ on Stack Overflow

Initialize 2D Array with characters c++

2 Answers 2

2 Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related