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#include <stdlib.h>
#include <stdio.h>

void print_matrix_pointer(int** matrix, int rows, int columns){
    int i, j;

    for(i = 0; i < rows; i++){
        for(j = 0; j < columns;  j ++){
            printf("%d ", matrix[i][j]);
        }
        printf("\n");
    }
}

int main(void) {
    int **arr_p;
    int xdim = 4;
    int ydim = 5;

    // first allocate array that points to arrays of rows
    // (notice the data type in sizeof operation)
    arr_p = (int**)malloc(ydim * sizeof(int *));
    if (!arr_p)
        return -1; // memory allocation failed

    for (int j = 0; j < ydim; j++) {
        arr_p[j] = (int*)malloc(xdim * sizeof(int));
        if (!arr_p[j]) {
            // memory allocation failed, release memory
            // will have to go through previously allocated rows
            for (int i = 0; i < j; i++) {
                free(arr_p[i]);
            }
            free(arr_p);
            return -1;
        }
        for (int i = 0; i < xdim; i++) {
            // fill matrix with values, multiplication table
            arr_p[j][i] = (i+1) * (j+1);
        }
    }

    print_matrix_pointer(arr_p, ydim, xdim);

    // release the memory
    for (int j = 0; j < ydim; j++) {
        free(arr_p[j]);
    }
    free(arr_p);
    return 0;
}