How to return a 2D array from a function in C?

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In C, pointers and arrays are closely related. Also, you usually need to pass the size of an array as a separate variable. Let’s start you with:

#include <stdio.h>

float** createArray(int m, int n)
{
    float* values = calloc(m*n, sizeof(float));
    float** rows = malloc(m*sizeof(float*));
    for (int i=0; i<m; ++i)
    {
        rows[i] = values + i*n;
    }
    return rows;
}

void destroyArray(float** arr)
{
    free(*arr);
    free(arr);
}

void drawLine(const float** coords, int m, int n);

int main(void)
{
    float** arr = createArray(2,2);
    arr[0][0] = 1;
    arr[0][1] = 1;
    arr[1][0] = 2;
    arr[1][1] = 2;
    drawLine(arr, 2, 2); 
    destroyArray(arr);
}

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