Program for Array slicing in c

The program takes 3 inputs:-

n = 6,  // length of array.
Array = {4,5,2,8,9,7} //Array input.
m = 3 //Slicing array in the third position of the array.

i.e. = {4,5,2},{8,9,7}

Output:-
the sum of sliced array = {12,14,9}    


       

How can I dynamically increase arrays after entering 'm' inputs for slicing?