C solution for merging two given *SORTED* arrays

array_merge.c

//
// solve the problem joel ... 
//
// compile & test with: cc array_merge.c -o testit && testit
//

#include <stdio.h>

int main() { 

    // given two seperate arrays, return a sorted array in lowest time possible.
    // assumption is that the two arrays are already independantly sorted
    // time for this solution is t ~= n1 + n2
    // with out the assumption of structured data, this would need to be a merge sort at something like t >= n1 ^ n2

    // I chose not to do shortcuts in this for clarity, for example I would normally have written line 38 as:
    //     merge[walkmerge++] = aa[walka++];
    
    // set up the arrays to merge
    int aa[] = {1, 3, 5, 7};
    int ab[] = {2, 4, 6, 8};

    // determing the length of arrays
    int lena = sizeof(aa) / sizeof(aa[0]); 
    int lenb = sizeof(ab) / sizeof(ab[0]);

    // allocate a new array for merge result
    int merge[ lena+lenb ];

    // init some counters
    int walka = 0, walkb = 0, walkmerge = 0; 

    // walk through both arrays with comparison to merge
    while ( walka<lena && walkb<lenb ) { 
        // compare current element of array A to current element or array B
        if (aa[walka] < ab[walkb]) {
            // array A element is smaller, append to merge
            merge[walkmerge] = aa[walka];
            // increment counter for merge and selected arrays
            walka++;
            walkmerge++;
        } else {
            // array B element is smaller (or equal), append to merge
            merge[walkmerge] = ab[walkb]; 
            // increment counter for merge and selected arrays
            walkb++;
            walkmerge++;
        }
    } 

    // store remaining elements of array a
    while ( walka<lena ) {
        merge[walkmerge] = aa[walka];
        // increment counters
        walka++;
        walkmerge++;
    }

    // store remaining elements of array b
    while ( walkb<lenb ) {
        merge[walkmerge] = ab[walkb]; 
        // increment counters
        walkb++;
        walkmerge++;
    }

    // output merge
    walkmerge = 0;
    int lenmerge = sizeof(merge) / sizeof(merge[0]);
    while ( walkmerge<lenmerge ) {
        printf("%i, ", merge[walkmerge]);
        walkmerge++;
    }
    printf("\n");
    return 0;
} 

// I guess I got caught up in the fact that data is never so structured, next time pay attention to initial parameteres as given