Calculating mean of each column in a 2D array in C?
<p>So let's say I have an 2D array of numbers:</p>

<pre><code>int a[WEEK][DAY] = {367, 654, 545, 556, 565, 526, 437,
                    389, 689, 554, 526, 625, 537, 468,
                    429, 644, 586, 626, 652, 546, 493,
                    449, 689, 597, 679, 696, 568, 522,
                    489, 729, 627, 729, 737, 598, 552};
</code></pre>

<p>How would I calculate the mean of each column? For example, 
(367+389+429+449+489)/5=424.6, and etc. I've figured out how to calculate the mean for each row but i'm having difficulties in doing it for each column. 
Here is What I have so far:</p>

<pre><code>#include &lt;stdio.h&gt;
#define WEEK 5
#define DAY 7
int main() {
/* or int a[][DAY] = {367, 654, 545, 556, 565, 526, 437, */
    int a[WEEK][DAY] = {367, 654, 545, 556, 565, 526, 437,
                        389, 689, 554, 526, 625, 537, 468,
                        429, 644, 586, 626, 652, 546, 493,
                        449, 689, 597, 679, 696, 568, 522,
                        489, 729, 627, 729, 737, 598, 552};
    int i, j, weektotal, total = 0;
    double meanval;
    printf("Week Mean hit\n");
    printf("-------------\n");
    for(i = 0; i &lt; WEEK; i++) {
        weektotal = 0;
        for(j = 0; j &lt; DAY; j++) {
            weektotal += a[i][j];
            total += a[i][j];
            }
    meanval = (double)weektotal/DAY;
    printf(" %d%10.2f\n", i+1, meanval);
    }

return 0;
}
</code></pre>

<p>This current code calculates mean for each of the 5 rows.</p>