Avichal solutions for Computer Applications [English] Class 10 ICSE chapter 5 - User - Defined Methods [Latest edition]

What is a pure method?

Write prototype of a method that accepts a boolean type value but does not return anything. 

In what way is OOPs principle polymorphism adopted in programming? 

Give the prototype of a method check which receives a character ch and an integer n and returns true or false. 

Write two advantages of using methods in a program.

Give the prototype of a method search which receives a sentence sentnc and a word wrd and returns 1 or 0. 

What is the role of the keyword void in declaring methods? 

What are the two ways of invoking methods? 

Differentiate between call by value and call by reference. 

What are the values of a and b after the following function is executed if the values passed are 30 and 50?

void paws(int a, int b) 
{ a = a + b; 
  b = a - b; 
  a = a - b;' 
System.out.println(a + "," + b); 
} 

Differentiate between formal parameter and actual parameter. 

Write a method prototype of the following: 

A method PosChar which takes a string argument and a character argument and returns an integer value.

A function to find the H.C.F and L.C.M of two numbers is defined below: 

public void hcflcm(int n1, int n2)
{
   num = .....?1?.....
   while(n1 != n2)
   {
      if (n1 > n2)
      n1 = ........?2?........ 
   elseif(......?3?......)
      n2 = n2 - n1;
   }
   hcf = n1;
   1cm = .......?4....... / hcf;
}

In the above function, there are some places left blank marked with ?1 ?, ?2?, ?3? and ?4? to be filled with conditions / expressions.

Based on the above discussion, answer the following questions:

1. What condition/expression will be filled in place of ?1?
   1. n1 + n2
   2. n1 / n2
   3. n1 * n2
   4. n1 % n2
2. What condition/expression will be filled in place of ?2?
   1. n1 − n2
   2. n1 + n2
   3. n1 * n2
   4. None
3. What condition/expression will be filled in place of ?3?
   1. n1 == n2
   2. n1 >= n2
   3. n1 < n2
   4. n1 <= n2
4. What condition/expression will be filled in place of ?4?
   1. num
   2. n2
   3. n1
   4. n1 + n2

The method which changes the state of an object is known as: 

Parameters used in method call statement are known as:

Parameters used in the method definition are called:

The process of calling a method in such a way that the change in the formal arguments reflects on the actual parameter is known as:

A method with many definitions is called:

A method may be associated with:

Which of the following type can be used for a non-returnable method?

A method body is enclosed within a pair of:

A method is invoked through an:

A method can return only ______ value to its caller program.

If a method does not return any value its return type is ______.

A method indicating the method name, return type along with method arguments is known as ______.

The variables used to receive the values in method header are known as ______.

Method in a Java program resides in ______.

The entire method body is enclosed under ______ brackets.

The ______ method performs some actions without returning any output.

A method contains ______ and ______.

Methods used with same name but different types of arguments are known as ______.

A method that is called by itself in its body is known as ______ method.

Calling and invoking a method is same. 

A method can use a single return statement. 

Overloading of methods even depends on return type.

A method cannot be defined without parameters. 

A method body is enclosed within curly brackets. 

Give the output of the following method definition and also write what mathematical operation it carries out:

void test1(int n) 
{
for (int x = 1; x <= n; x++) 
if (n % x == 0) 
System.out.println(x); 
}

if 12 is passed to n. 

Give the output of the following method definition and also write what mathematical operation it carries out:  

void test2(int a, int b)
{
    while( a != b)
    {
      if ( a > b)
        a = a − b;
      else
        a = b − a;  
    }
    System.out.println(a);
}

if 4 and 17 are passed to the function.

Give the output of the following method definition and also write what mathematical operation it carries out: 

void test3(char c)
{
    System.out.println( (int) c);
}

if 'm' is passed to c. 

Give the output of the following method definition and also write what mathematical operation it carries out: 

void test4(String x, String y)
{
    if(x.compareTo(y) > 0)
        System.out.println(x);
    else
        System.out.println(y);
}

if "AMIT" and "AMAN" are passed to the method.

A method is a program module that is used simultaneously at different instances in a program. It helps a user to reuse the same module multiple times in the program. Whenever you want to use a method in your program, you need to call it through its name. Some of the components/features of a method are as described below: 

1. It defines the scope of usage of a method in the user's program.
2. It is the value passed to the method at the time of its call.
3. It is a return type that indicates that no value is returned from the method.
4. It is an object oriented principle which defines method overloading.

Write the appropriate term used for each component/ feature described above.

Define a method.

What is meant by method prototype?

What are the two ways of invoking methods? 

When a method returns the value, the entire method call can be assigned to a variable. Do you agree with the statement? 

When a method is invoked how many values can be returned from the method?

Debug the error and rewrite the following method prototype:

int sum(x,y);

Debug the error and rewrite the following method prototype:

float product(a,int y);

Debug the error and rewrite the following method prototype:

float operate(int x, float=3.4);

Debug the error and rewrite the following method prototype:

float sum(int x,y);

Write down the main method which calls the following method: 

int square(int a)
{
    return(a*a);
}

What happens when a method is passed by reference? Explain.

In what situation does a method return a value?

Differentiate between pure and impure methods. 

Write a method which is used to swap the values of two memory locations by using a third variable.

Write a method which is used to swap the values of two memory locations without using a third variable. 

Differentiate between call by value and call by reference. 

What are the advantages of defining a method in a program? 

What is meant by method overloading? 

In what way method overloading is advantageous? 

Define Return data type.

Define Access specifier.

Define Parameter list.

Define Recursive method.

Define Method signature.

Explain the method of a return statement in Java programming. 

Differentiate between formal parameter and actual parameter. 

What is the role of the keyword void in declaring methods? 

If a method contains several return statements, how many of them will be executed? 

Which OOP principle implements method overloading? 

How are the primitive data types passed to a method? 

How are the reference data types passed to a method?

Write a program in Java using a method Discount(), to calculate a single discount or a successive discount. Use overload methods Discount(int), Discount(int,int) and Discount(int,int,int) to calculate single discount and successive discount respectively. Calculate and display the amount to be paid by the customer after getting discounts on the printed price of an article.

Sample Input: Printed price: ₹ 12000
Successive discounts = 10%, 8%
                                  = ₹ (12,000 − 1200)
                                  = ₹ (10,800 − 864)
Amount to be paid   = ₹ 9936 

Write a program to input a three digit number. Use a method int Armstrong(int n) to accept the number. The method returns 1, if the number is Armstrong, otherwise zero(0).  

Sample Input: 153
Sample Output: 153 = 1³ + 5³ + 3³ = 153
                           It is an Armstrong Number.

Write a program to input a number and check and print whether it is a Pronic number or not. (Pronic number is the number which is the product of two consecutive integers).

Examples: 12 = 3 × 4 
20 = 4 × 5
42 = 6 × 7

Write a program to enter a two digit number and find out its first factor excluding 1 (one). The program then find the second factor (when the number is divided by the first factor) and finally displays both the factors. Hint: Use a non-return type method as void fact(int n) to accept the number. 

Sample Input: 21
The first factor of 21 is 3
Sample Output: 3, 7
Sample Input: 30
The first factor of 30 is 2
Sample Output: 2, 15 

Write a method fact(int n) to find the factorial of a number n. Include a main class to find the value of S where: 

S = `(n!)/(m!(n-m))` 
where, n! = 1 × 2 × 3 × .................................. × n

Write a program using a method called area() to compute area of the following: 

1. Area of circle = `22/7 "*""r""*""r"`
2. Area of square = side * side
3. Area of rectangle = length * breadth 

Display the menu to display the area as per the user's choice.

Write a program using method name Glcm(int,int) to find the Lowest Common Multiple (LCM) of two numbers by GCD (Greatest Common Divisor) of the numbers. GCD of two integers is calculated by continued division method. Divide the larger number by the smaller, the remainder then divides the previous divisor. The process is repeated till the remainder is zero. The divisor then results in the GCD.

LCM = `"product of two numbers"/("GCD")`

Write a program in Java to accept a word. Pass it to a method Magic(String str). The method checks the String for the presence of consecutive letters. If two letters are consecutive at any position then the method prints "It is a Magic String", otherwise it prints "It is not a Magic String".  

Sample Input: computer
Sample Output: It is not a Magic String
Sample Input: DELHI
Sample Output: It is a Magic String 

Write a program using a method Palin( ), to check whether a String is a: Palindrome or not. A Palindrome is a String that reads the same from the left to right and vice versa.

Sample Input: MADAM, ARORA, ABBA, etc. 

Write a program in Java to accept a String from the user. Pass the String to a method Display (String str) which displays the consonants present in the String. 

Sample Input: computer
Sample Output: c
                            m
                            p
                            t
                            r

Write a program in Java to accept a String from the user. Pass the String to a method Change (String str) which displays the first character of each word after changing the case (lower to upper and vice versa).

Sample Input: Delhi public school
Sample Output: d
                            P
                            S

Write a program in Java to accept the name of an employee and his/her annual income. Pass the name and the annual income to a method Tax(String name, int income) which displays the name of the employee and the income tax as per the given tariff: 

Write a program in Java to accept a String from the user. Pass the String to a method First(String str) which displays the first character of each word. 

Sample Input: Understanding Computer Applications
Sample Output: U
                            C
                            A

Write a program to accept 10 numbers in a Single Dimensional Array. Pass the array to a method Search(int m[], int ns) to search the given number ns in the list of array elements. If the number is present, then display the message 'Number is present' otherwise, display 'number is not present'. 

Write a class with the name Area using method overloading that computes the area of a parallelogram, a rhombus and a trapezium.

Formula: Area of a parallelogram (pg) base*ht

Area of a rhombus (rh) = `1/2"*d1*d2"` (where, d1 and d2 are the diagonals)

Area of a trapezium (tr) = `1/2"*(a+b)*h"` (where, a and b are the parallel sides, h is the perpendcular distance between the parallel sides) 

Write a class with the name Perimeter using method overloading that computes the perimeter of a square, a rectangle and a circle. 

Formula: Perimeter of a square 4*s

Perimeter of a rectangle = 2*(1 +b)

Perimeter of a circle = `2"*"22/7"*r"`

Design a class overloading and a method display() as follows: 

1. void display(String str, int p) with one String argument and one integer argument. It displays all the uppercase characters if 'p' is 1 (one) otherwise, it displays all the lowercase characters.
2. void display(String str, char chr) with one String argument and one character argument. It displays all the vowels if chr is 'v' otherwise, it displays all the alphabets.  

Design a class overloading a method calculate() as follows:

1. void calculate(int m, char ch) with one integer argument and one character argument. It checks whether the integer argument is divisible by 7 or not, if ch is 's', otherwise, it checks whether the last digit of the integer argument is 7 or not.
2. void calculate(int a, int b, char ch) with two integer arguments and one character argument. It displays the greater of integer arguments if ch is 'g' otherwise, it displays the smaller of integer arguments. 

Design a class to overload a method compare() as follows:

1. void compare(int, int): to compare two integers values and print the greater of the two integers.
2. void compare(char, char): to compare the numeric value of two characters and print with the higher numeric value.
3. void compare(String, String): to compare the length of the two strings and print the longer of the two. 

Design a class to overload a method series() as follows:

1. double series (double n) with one double argument and returns the sum of the series. 
   sum `1/1 + 1/2 + 1/3 + ................+ 1/n`
2. double series (double a, double n) with two double arguments and returns the sum of the series.
   sum `1/a^2 + 4/a^5 + 7/a^8 + 10/a^11 + .....................` to n terms

Design a class to overload the method display(........) as follows:

1. void display(int num): checks and prints whether the number is a perfect square or not.
2. void display(String str, char ch): checks and prints if the word str contains the letter ch or not.
3. void display(String str): checks and print the number of special characters present in the word str. 

Write a suitable main() method.

Design a class to overload the method display(.......) as follows: 

1. void display(String str, char ch): checks whether the word str contains the letter ch at the beginning as well as at the end or not. If present, print 'Special Word' otherwise print 'No special word'.
2. void display(String str1, String str2): checks and prints whether both the words are equal or not.
3. void display(String str, int n): prints the character present at n^th position in the word str. 

Write a suitable main() method. 

Design a class to overload a function volume() as follows: 

1. double volume (double R): with radius (R) as an argument, returns the volume of a sphere using the formula.
   V = 4/3 × 22/7 × R³
2. double volume (double H, double R): with height(H) and radius(R) as the arguments, returns the volume of a cylinder using the formula.
   V = 22/7 × R² × H
3. double volume (double L, double B, double H): with length(L), breadth(B) and Height(H) as the arguments, returns the volume of a cuboid using the formula.