Merge two presorted lists

Refer: Mathbits.com

//Function to merge two pre-sorted arrays
void merge_sort(apvector &arrayA, apvector &arrayB, apvector &arrayC)
{
int indexA = 0; // initialize the Array Indices
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 index
}
else
{
arrayC[indexC] = arrayB[indexB];
indexB++; //increase the index
}
indexC++; //move to the next position in the new array
}
// Push remaining elements to end of new array when 1 feeder array is empty
while (indexA < arrayA.length( ))
{
arrayC[indexC] = arrayA[indexA];
indexA++;
indexC++;
}
while (indexB < arrayB.length( ))
{
arrayC[indexC] = arrayB[indexB];
indexB++;
indexC++;
}
return;
}