Avichal solutions for Computer Applications [English] Class 10 ICSE chapter 1.7 - Conditional Statements in Java [Latest edition]

What is control variable in a switch statement? 

In a switch statement, why is it necessary to use break after each case? 

Use switch case statement for the given program snippet:

if(a == 100) 
c = a * 2; 
if(a == 200) 
c = a * 4; 
if(a == 600) 
c = a * 10; 

Use if else statement for the given snippet:

String st = (a > 0) ? (a % 2 == 0) ? "Positive even" : "Positive odd" : "Negative number"; 

Find errors in the following snippet:

int a = 5, b = 3; 
if (a <= b) 
   System.out.println(a); 
else 
   System.out.println(c = a + b); 

Find errors in the following snippet:

int p = 10; 
switch (p) 
{
case1: q = p * 2; 
break; 
case2: q = p + 2;
break; 
case3: q = p − 2; 
break; 
}

Rewrite the following program segment using if-else statements instead of the ternary operator: 
String grade = (mark >= 90) ? “A” : (mark >= 80) ? “B” : “C”;

If m, n, p are the three integers, then which of the following holds true, if (m == n) && (n != p)? 

A compound statement can be stated as: 

If ((p > q) && (q > r)) then:

(where p, q and r are three integer numbers) 

if (a < b) 
    c = a;
else
    c = b;

It can be written as:

If (a < b && a < c)

(where a, b and c are three integer numbers)

if statement is also called as a conditional statement. 

A conditional statement is essentially formed by using relational operators. 

An if-else construct accomplishes 'fall through'. 

In a switch case, when the switch value does not match with any case then the execution transfers to the default case. 

The break statement may not be used in a switch statement.

Predict the output:

int m = 3, n = 5, p = 4; 
if (m == n) && (n != p)
   {
   System.out.println(m * n); 
   System.out.println(n % p); 
   }
if ((m != n) || (n == p)) 
   {
   System.out.printIn(m + n); 
   System.out.println(m − n); 

Predict the output:

p = 1

int a = 1, b = 2, c = 3; 
switch(p)
   {
   case 1: a++; 
   case 2: ++b;
      break; 
   case 3: c--; 
   }
System.out.println(a + "," + b + "," + c);

Predict the output:

p = 3

int a = 1, b = 2, c = 3; 
switch(p) 
   {
   case 1: a++;
   case 2: ++b; 
       break;
   case 3: c--; 
   }
System.out.println(a + "," + b + "," + c);

Convert the following construct as directed:

switch case construct into if-else-if:

switch(n)
{
case 1:
    s = a + b; 
    System.out.println("Sum = " + s);
    break;
case 2:
    d = a − b;
    System.out. println("Difference = " + d); 
    break;
case 3:
    p = a * b;
    System.out.println("Product = " + p); 
    break; 
default:
    System.out.println("Wrong Choice!"); 
}

Convert the following construct as directed:

if-else-if construct into switch case:

if (var == 1) 
    System.out.println("Distinction"); 
else if (var == 2) 
    System.out.println("First Division"); 
else if (var == 3) 
    System.out.println("Second Division"); 
else 
    System.out.println("invalid");

What is meant by conditional statements in JavaScript?

What is the significance of System.exit(0)?

Is it necessary to include default case in a switch statement? Justify. 

What will happen if break statement is not used in a switch case? Explain. 

When does Fall through occur in a switch statement? Explain. 

What is a compound statement? 

Give an example of a compound statement.

Explain if-else-if construct with an example.

Give two differences between the switch statement and the If-else statement.

Write a program to input three numbers (positive or negative). If they are unequal then display the greatest number otherwise, display they are equal. The program also displays whether the numbers entered by the user are 'All positive', 'All negative' or 'Mixed numbers'.

Sample Input: 56, -15, 12
Sample Output: The greatest number is 56.
                          Entered numbers are mixed numbers.

A triangle is said to be an 'Equable Triangle', if the area of the triangle is equal to its perimeter. Write a program to enter three sides of a triangle. Check and print whether the triangle is equable or not.

For example, a right angled triangle with sides 5, 12 and 13 has its area and perimeter both equal to 30. 

A special two-digit number is such that when the sum of its digits is added to the product of its digits, the result is equal to the original two-digit number. Example: Consider the number 59.
Sum of digits = 5 + 9 = 14
Product of its digits = 5 x 9 = 45
Sum of the sum of digits and product of digits = 14 + 45 = 59
Write a program to accept a two-digit number. Add the sum of its digits to the product of its digits. If the value is equal to the number input, output the message “Special 2-digit number” otherwise, output the message “Not a special 2-digit number”

The standard form of quadratic equation is given by: 

ax² + bx + c = 0, where d = b² − 4ac, is known as discriminant that determines the nature of the roots of the equation as: 

Write a program to determine the nature and the roots of a quadratic equation, taking a, b, c as input. If d = b² − 4ac is greater than or equal to zero, then display 'Roots are real', otherwise display 'Roots are imaginary'. 

The roots are determined by the formula as: 

`"r"1 = (-b + sqrt(b^2 - 4ac))/(2a), "r"2 = (-b - sqrt(b^2 - 4ac))/(2a)`

An air-conditioned bus charges fare from the passengers based on the distance travelled as per the tariff given below:  

Design a program to input distance travelled by the passenger. Calculate and display the fare to be paid. 

An ICSE school displays a notice on the school notice board regarding admission in Class XI for choosing stream according to marks obtained in English, Maths and Science in Class 10 Council Examination.  

Print the appropriate stream allotted to a candidate. Write a program to accept marks in English, Maths and Science from the console.

A bank announces new rates for Term Deposit Schemes f ir their customers and Senior Citizens as given below: 

The senior citizen rates are applicable to the customers whose age is 60 years or more. Write a program to accept the sum (p) in term deposit scheme, age of the customer and the term. The program displays the information in the following format: 

A courier company charges differently for 'Ordinary' booking and 'Express' booking based on the weight of the parcel as per the tariff given below: 

Write a program to input weight of a parcel and type of booking ('O' for ordinary and 'E' for express). Calculate and print the charges accordingly. 

Write a program to input a number and check whether it is a perfect square or not. If the number is not a perfect square then find the least number to be added to input number, so that the resulting number is a perfect square. 

Example 1:
Sample Input: 2025
`sqrt(2025)` = 45
Sample Output: It is a perfect square.

Example 2:
Sample Input: 1950
`sqrt(1950)` = 44.1588.........
Least number to be added = 452 − 1950 = 2025 − 1950 = 75

Write a program that accepts three numbers from the user and displays them either in "Increasing Order" or in "Decreasing Order" as per the user's choice. 

Choice 1: Ascending order
Choice 2: Descending order
Sample Inputs: 394, 475, 296
Choice: 2 
Sample Output:
First number : 475
Second number : 394
Third number : 296
The numbers are in decreasing order. 

Write a menu driven program to calculate:

1. Area of a circle = p*r*r, where p = `22/7`
2. Area of a square = side*side
3. Area of a rectangle = length*breadth

Enter 'c' to calculate area of circle, 's' to calculate area of square and 'r' to calculate area of rectangle. 

Write a program using switch case to find the volume of a cube, a sphere and a cuboid. For an incorrect choice, an appropriate error message should be displayed. 

1. Volume of a cube = s * s * s
2. Volume of a sphere = `4/3` π*r*r*r (π = `22/7`)
3. Volume of a cuboid = l*b*h 

The relative velocity of two trains travelling in opposite directions is calculated by adding their velocities. In case, the trains are travelling in the same direction, the relative velocity is the difference between their velocities. Write a program to input the velocities and length of the trains. Write a menu driven program to calculate the relative velocities and the time taken to cross each other.

In order to purchase an old car, the depreciated value can be calculated as per the tariff given below:

Write a menu driven program to input showroom price and the number of years the car is used ('1' for one year old, '2' for two years old and so on). Calculate the depreciated value. Display the original price of the car, depreciated value and the amount to be paid. 

You have a saving account in a bank with some balance amount in your account. Now, you want to perform the following tasks, as per your choice. The tasks are as under: 

1. Money Deposited
2. Money Withdrawn
3. Check balance
0. To quit

Write a menu driven program to take input from the user and perform the above tasks. The program checks the balance before withdrawal and finally displays the current balance after transaction. For an incorrect choice, an appropriate message should be displayed.