Two dimensional arrays

[Ozwurld]

Hello all, can someone please help me get the function disparray to compile.

//Simpe code on passing arrays into other functions for modification

#include <iostream>
using namespace std;

void dispArray(int **array)
{
    for ( unsigned int i = 0; i < 2; i++)
    {
		for ( unsigned int j =0; j < 3; j++)
			cout << array[i][j] << endl;   
    }
}

int main()
{
	int myArray[2][3] = {1,2,3,4,5,6};
	dispArray(myArray);
	
	//cout << myArray[0][1] ; 
}

-Thanks!

[giblit]

You should setup your 2d array with something like this int myArray[2][3] = { {1,2,3}, {4,5,6}}; Also to you can't pass a 2d array like that. The compiler needs to know how many columns there are in each row. So something like this void dispArray(int array[][3]) I would also suggest avoid using magic numbers such as 2 and 3.

[Ozwurld]

Thanks for the reply giblit, but the problem is i do not know the number of the thing in my array at runtime, how would i overcome this?

[giblit]

If you don't know the size of the array at run time I think there is a problem with your program. Maybe you mean you don't know the size at compile time? For that you could either use templates or pass the size to the function.

[jlb]

Have you considered std::vector instead of the array?

It is possible to do what you want, if you're willing to use a little pointer magic.

#include <iostream>

using namespace std;

void dispArray(int *array, size_t col, size_t row)
{
    for(size_t i = 0; i < col; i++)
    {
        for(size_t j =0; j < row; j++)
            cout << *(array + i + j) << " ";
      cout << endl;
    }
}

int main()
{
    int myArray[2][3] = {{1,2,3},{4,5,6}};

    dispArray(myArray[0], 2, 3);
}

And remember Variable Length Arrays are not supported by the current C++ standard, so if you don't know the size of the array at compile time you'll either need to use new/delete to create your array or use std::vector instead.

[Atyab]

You can Dynamically Allocate Memory to 2D Array like this:

#include <iostream>
using namespace std;

void printArray(int**,int,int);

int main()
{
    int **arr;
    
    /*
     * Take Input from anywhere after the program starts (RUNTIME)
     * For Demonstration I am taking r=2 and c=3
     * */
    int r=2,c=3;
    
    //Dynamic Allocation of a 2D Array
    arr = new int*[r];

    for(int i=0;i<r;i++)
    {
        arr[i] = new int[c];
    }

    //Initializing 2D Array by 0
    for(int i=0;i<r;i++)
        for(int j=0;j<c;j++)
            arr[i][j] = 0;

    printArray(arr,r,c);

    cout << endl;
    return 0;
}

void printArray(int **inp, int r, int c)
{
    for(int i=0;i<r;i++)
    {
        for(int j=0;j<c;j++)
            cout << inp[i][j];
        cout << endl;
    }
}

[Ozwurld]

Thanks Atyab & jlib, i was looking for something like that :).

[jlb]

I really recommend you think about using std::vector, it'll be much cleaner and less error prone.