c++ 2D dynamic array defaulting to size 4

[Lodi]

Hi. Below is my c++ code. I am trying to create a 2D dynamic array which is created with the correct number of rows and columns. However, I can't seem to access row and column values above 4. Even sizeof(array) and sizeof(array[0]) both output 4.

int x;
int y = 5;
float** g_schedule;

int main(){
   x = findSize();

   g_schedule = new float* [x];
   for (int row = 0;row < x;row++){
	g_schedule[row] = new float[y];
   } 
}

[48T7M4Gy]

#include <iostream>

int main()
{
    int x = 7;  // number of rows
    int y = 5; // number of columns
    
    // Create matrix
    int** g_schedule = new int*[x];
    for(int i = 0; i < x; ++i)
        g_schedule[i] = new int[y];
        
    // Generate values
    for(int i = 0; i < x; i++)
    {
        for(int j = 0; j < y; j++)
            g_schedule[i][j] = (i +j) * (i * j);
    }
    
    // Display matrix 
    for(int i = 0; i < x; i++)
    {
        for(int j = 0; j < y; j++)
            std::cout << g_schedule[i][j] << '\t';
        std::cout << '\n';
    }
    
    // Display "size"
    std::cout << "Size (ie no. of elements): " << x * y << '\n';
}

0	0	0	0	0	
0	2	6	12	20	
0	6	16	30	48	
0	12	30	54	84	
0	20	48	84	128	
0	30	70	120	180	
0	42	96	162	240	
Size (ie no. of elements): 35

http://stackoverflow.com/questions/936687/how-do-i-declare-a-2d-array-in-c-using-new

[Peter87]

g_schedule is a pointer so sizeof(g_schedule) will give you the size of a pointer.
g_schedule[0] is also a pointer so sizeof(g_schedule[0]) will also give you the size of a pointer.
To know the size you need to keep track of it using variables.

[48T7M4Gy]

The size, in the conventional sense of a 2-d array, is already given by the 2 variables x and y.

sizeof(int) = 4 may be more than a coincidence.

Maybe the fact that OP hasn't initialised x is a factor too.

But despite all of this, we haven't seen what findSize() does.

[Lodi]

Thank you Peter87 and kemort, works perfectly now. The example also made it that much more easier to test. I found it awkward that 4 was always the output, but did not interrogate my code further.