Page 457 - Computer science 868 Class 12
P. 457
The output of the preceding program is as follows:
Program 3 A base class called Number is defined which finds the number of digits in a number. The
details of the class is given below.
Class name : Number
Data Members
num : Integer to store number
len : Length of the number, i.e., total number of digits
Member Methods
Number(int a) : Initialises num = a and len to 0
void countdigits() : Counts the number of digits in number num
void print() : Prints the number and number of digits
A derived class Armstrong is defined to check if a given number is an Armstrong number or
not. A number is said to be Armstrong if sum of its digits raised to the power of length of the
number is equal to the number itself. For example,
371 = 3 + 7 + 1 3
3
3
4
4
1634 = 1 + 6 + 3 + 4 4
4
5
5
54748 = 5 + 4 + 7 + 4 + 8 5
5
5
Thus, 371, 1634 and 54748 are all examples of Armstrong numbers.
The details of the class is given below.
Class name : Armstrong
Data Members
sum : Stores sum of the digits raised to the power of the length of the
number
Member Methods
Armstrong(….) : Parameterised constructor to initialise the variables of the
base and derived classes
void sumdigit() : Calculates the sum of the digits raised to the power of the
length of the number
void print() : Prints the details of the number by calling print() of the base
class. Also checks and prints whether the number num is an
Armstrong number or not
Define the above classes. Also write the main method to create object of the derived class
and call the methods to implement the above.
1 class Number
2 { protected int num,len;
3 Number(int a) //base class constructor
455
Inheritance, Interfaces and Polymorphism 455

