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copied!<p>It looks like you're basically implementing a dynamic Matrix object here. You want something like:</p> <pre><code>typedef struct _object{ int rowsAmount; int columsAmount; int* matrix; int** rows; } object; object* newObject(int ra, int ca){ object* o = malloc(sizeof(object)); o->rowsAmount = ra; o->columsAmount = ca; o->matrix = malloc(ra * ca * sizeof(int)); o->rows = malloc(ra * sizeof(int*)); for (size_t i = 0; i != ra; ++i) o->rows[i] = o->matrix + (i * ca); return o; } </code></pre> <p>You should also create a destructor function <code>destroyObject</code>, which similarly <code>free</code>s all the memory allocated for <code>o</code> and <code>o->matrix</code>.</p> <p><em><strong>Edit</em></strong>:</p> <p>However, your comment that:</p> <blockquote> <p>"I'm just trying to learn c, this is only about the setting the size. I just happened to try it with 2 arrays"</p> </blockquote> <p>...makes this question somewhat confusing, because it indicates you are not, in fact, trying to create a matrix (2D array) despite your use of "row"/"column" terminology here, but that you simply want to understand how to dynamically allocate arrays in C.</p> <p>If that's the case, an array in C is dynamically allocated using a pointer variable and <code>malloc</code>:</p> <pre><code>size_t array_size = 10; /* can be provided by user input */ int* array = malloc(sizeof(int) * array_size); </code></pre> <p>And then later, the dynamically-allocated array must be freed once you are finished working with it:</p> <pre><code>free(array); </code></pre>

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