2017 ISC Theoretical Paper on Computer with Solutions

Question 2

(a): What is an interface? How it is different from a class? (2)

An interface is like a class but not a class. In an interface, the data members declared are always static final and methods are declared only. A class can implement an interface but can’t extend an interface.

A class contains data members and method members. Methods are defined in a class. The data members and methods members of a class can have any access specifiers – public, private, default or protected and they may be either instance of static member. We can create objects of a defined class.

An interface contains data members which must be static final and method declaration which should be final only. We can’t create objects of an interface but a class can implements number of interfaces.

(b): Convert the following infix expression to postfix form (2)

P * Q / R + (S+T)

PQ*R/ST++

(c): A matrix P[15][10]is stored with each element requiring 8 bytes of storage. If the base address at P[0][0] is 1400, determine the address at P [10][7] when the matrix is stored in row major wise. (2)

(Row major order) Address(Arr[j,k])=base(Arr)+w[n(j-1)+(k-1)] - 'w' is the bytes required for each location and 'n' is length of 2nd dimension

1400 + 8 * [10*9+6]

1400+8*96

2168

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