Cannot see what is wrong with my code: Currently trying to sort an array using merge sort.

Code:

#include <iostream>
#define SIZE 4
void mergeSort(float arraySorted[], float arrayTemp[], int LHS, int RHS);
void mergeBack(float arraySorted[], float arrayTemp[], int LHS, int middle, int RHS);
void main(){
int Counter=0;
float arrayOne[SIZE] = {65, -72, 54, 238};
float arrayTwo[SIZE];
for (Counter=SIZE-1;Counter>=0;Counter--){
std::cout << arrayOne[Counter] << std::endl;
}
std::cout << "Something about sorting:" << std::endl;
mergeSort(arrayOne, arrayTwo, 0, SIZE-1);
for (Counter=SIZE-1;Counter>=0;Counter--){
std::cout << arrayOne[Counter] << std::endl;
}
std::cout << "Blah" << std::endl;
}
void mergeSort(float arraySorted[], float arrayTemp[], int LHS, int RHS){
int Counter, middle;
if (RHS > LHS){
middle = (LHS + RHS) / 2;
mergeSort(arraySorted, arrayTemp, LHS, middle);
mergeSort(arraySorted, arrayTemp, (middle+1), RHS);
mergeBack(arraySorted, arrayTemp, LHS, middle, RHS);
}
}
void mergeBack(float arraySorted[], float arrayTemp[], int LHS, int middle, int RHS){
int LHSEnd, arraySize, arrayPosition, Counter = 0;
LHSEnd = (middle -1);
arrayPosition = (LHS);
while ((LHS <= LHSEnd) && (middle <= RHS)){
if (arraySorted[LHS] <= arraySorted[middle]){
arrayTemp[arrayPosition] = arraySorted[LHS];
arrayPosition = arrayPosition + 1;
LHS = LHS + 1;
}else{
arrayTemp[arrayPosition] = arraySorted[LHS];
arrayPosition = arrayPosition + 1;
middle = middle + 1;
}
}
while(LHS <= LHSEnd){
arrayTemp[arrayPosition] = arraySorted[LHS];
LHS = LHS + 1;
arrayPosition = arrayPosition + 1;
}
while(middle <= RHS){
arrayTemp[arrayPosition] = arraySorted[middle];
middle = middle + 1;
arrayPosition = arrayPosition + 1;
}
LHS=-SIZE-1;
for(Counter=SIZE;Counter>=0;Counter--){
arraySorted[LHS] = arrayTemp[LHS];
LHS = LHS + 1;
}
}

Also I am unsure of how to work out the Big-0 or how many procedures it requires to work this out.

If anyone can help me with either of my problems I would be very grateful.