C++ interview question: How to merge one array into another also known as merge sort

How to merge one array into another. A good example would involve a merge sort like:
void MergeSort(apvector &arrayA, apvector &arrayB, apvector &arrayC)
{
int indexA = 0; // initialize variables for the subscripts
int indexB = 0;
int indexC = 0;

while((indexA < arrayA.length( )) && (indexB < arrayB.length( )) { if (arrayA[indexA] < arrayB[indexB]) { arrayC[indexC] = arrayA[indexA]; indexA++; //increase the subscript } else { arrayC[indexC] = arrayB[indexB]; indexB++; //increase the subscript } indexC++; //move to the next position in the new array } // Move remaining elements to end of new array when one merging array is empty while (indexA < arrayA.length( )) { arrayC[indexC] = arrayA[indexA]; indexA++; indexC++; } while (indexB < arrayB.length( )) { arrayC[indexC] = arrayB[indexB]; indexB++; indexC++; } return; } The one powerful concept of arrays is their use to traverse the array as you can access each element using the same expression. All you need to is have an interated statement in which the variable i can be used as a counter incrementing from zero to the length minus one.