mergesortarray.cpp

#include<iostream>
#include<cstdlib>
using namespace std;
// we are creating function pointer that points to the array that we will be returned.
int *mergeArray(int *arr1, int *arr2, int size1, int size2) {
    if(size1 == 0) {
        return arr2;
    }
    if(size2 == 0) {
        return arr1;
    }
    int *arr = new int[size1 + size2];
    int index1 = 0, index2 = 0, index = 0;
    while(index1 < size1  && index2 < size2) {
        if(arr1[index1] <= arr2[index2]) {
            arr[index] = arr1[index1];
            index1++;
        }
        else {
            arr[index] = arr2[index2];
            index2++;
        }
        index++;
    }
    for( int inx = index1; inx < size1; ++inx)
    {
      arr[index] = arr1[inx];
      ++index;
    }
    for( int inx = index2; inx < size2; ++inx)
    {
      arr[index] = arr2[inx];
      ++index;
    }
    return arr;
}

int main() {
    int arr1[] = {1,2,3,4,5,6,7};
    int arr2[] = {3,4,5,7,8,9,10, 11};

    int size1 = sizeof(arr1)/sizeof(arr1[0]);
    int size2 = sizeof(arr2)/sizeof(arr2[0]);

    int *newArr = mergeArray(arr1, arr2, size1, size2);
    cout<<"Merged Array: "<<endl;
    for(int i = 0; i < size1+size2; i++) {
        cout<<newArr[i]<<"  ";
    }
    cout<<endl;
    return 0;
}