Write a C$++$ program to create $2$ arrays below:

int array$1[]=\{1,2,3,4,5\}$;

int size$1=$ sizeof$($array$1)/$ sizeof$($int$)$;

int array$2[]=\{4,5,6,7,8\}$;

int size$2=$ sizeof$($array$2)/$ sizeof$($int$)$;

Then write a function that takes two pointers to the above arrays and their sizes as arguments. The function should return a pointer to a new array that contains the combination of the elements of the two input arrays. The function should also modify the size argument to be the size of the new array. Use below function prototype:

int$*$ unionArrays$($int$*$ array$1,$ int size$1,$ int$*$ array$2,$ int size$2,$ int& size$)$

To remove the duplicate, you may use Boolean data type declaration below:

bool isDuplicate $=$ false;

Sample IO format of the program is as shown below:

New array: $12345678$

Size of the new array: $8$