Implementation of merge sort in C++

gistfile1.mak

CPPFLAGS=-g -c -std=c++0x

LDFLAGS=-g

RM=rm -f

SOURCES=merge-sort.cc
OBJECTS=merge-sort.o

all:	merge-sort

merge-sort:	$(OBJECTS)
	$(CXX) $(LDFLAGS) -o merge-sort $(OBJECTS)
merge-sort.o:	merge-sort.cc merge-sort.h
	$(CXX) $(CPPFLAGS) merge-sort.cc
clean:
	$(RM) $(OBJECTS)

mergesort.cpp

#include "merge-sort.h"

using std::cout;
using std::endl;

int* merge2(int *A, int len_A, int *B, int len_B) {
  /*  
   *
   *  Takes arrays A and B as input, outputs sorted array containing all the
   *  elements from A and B.
   *
   *  Requirements: A and B must be sorted arrays
   *
   */

  int N = len_A + len_B;

  int *C = new int[N];

  int i=0;
  int j=0;
  int k=0;

  //Populate array C with elements in sorted order from arrays A and B
  for(; k<N; k++){
    if ((i>=len_A) || (j>=len_B)){
      break;
    }

    if (A[i] < B[j]) {
      C[k] = A[i];
      i++;
    }
    else {
      C[k] = B[j];
      j++;
    }
  }

  //Add leftover elements in A
  for(;i<len_A; i++) {
    C[k] = A[i];
    k++;
  }
  //Add leftover elements in B

mergesort.h

#include<iostream>
#include<cstdlib>

//MergeSort algorithm implementation
int* merge2(int *A, int len_A, int *B, int len_B);
int* sort2(int *A, int len_A);

//Utility Functions
int* genArray(size_t size);
void printArray(int *array, int l);
void testMergeSort();