Merits:
(a) We can easily access each element of array.
(b) Not necessity to declare too many variables.
(c) Array elements are stored in continuous memory location.

Demerits:
(a) Wastage of memory space. We cannot change size of array at the run time.
(b) It can store only similar type of data

Evaluation of any expression is from left to right. Preincrement is faster because it doesn't need to save the current value for next instruction whereas Postincrement needs to saves current value to be incremented after execution of current instruction.

Major differences between arrays and linked lists are: (i)  In array consecutive elements are stored in consecutive memory locations whereas in linked list it not so. (ii)  In array address of next element is consecutive and whereas in linked list it is specified in the address part of each node.(iii) Linked List makes better use of memory than arrays.(iv) Insertion or deletion of an element in array is difficult than insertion or deletion in linked list

(i) It increases the portability.
(ii) It simplify the complex declaration and improve readability of the program.

Library Functions are predefined functions and stored in .lib files.