Java Control Structures Quiz

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Questions and Answers

What is the purpose of the break statement in a switch construct?

To exit the switch block. (correct)

To repeat the current case.

To default to the last case.

To skip the next case.

Which data types can be used as case constants in a switch statement?

Only long and double types.

Only boolean types.

Numeric and character data types. (correct)

Any reference type.

What happens if a switch variable does not match any case constants?

The default case is executed if present. (correct)

The program executes the statements after the switch block.

The program terminates immediately.

The program enters an infinite loop.

Where must the default case be positioned in a switch statement?

At the end of the switch block. Signup and view all the answers

Which statement is true regarding the case constants in a switch statement?

They cannot have the same value. Signup and view all the answers

What will happen if you forget to assign a value to the switch variable before entering the switch construct?

The control will not enter the switch block. Signup and view all the answers

In the example given, if 'day' evaluates to '5', what will be the output?

Friday Signup and view all the answers

What keyword is used to start a switch statement?

switch Signup and view all the answers

What will be the output when the variable 'day' is set to 5 in the switch statement?

Friday Signup and view all the answers

Which statement best describes the role of the loop control variable in a while loop?

It evaluates the Boolean expression within the loop. Signup and view all the answers

What is the correct syntax for a while loop?

while (boolean-exprsn) { statement; } Signup and view all the answers

If the 'day' variable is set to 8, what will the switch statement output?

Invalid entry Signup and view all the answers

In the repetition statement definition, what is meant by the condition becoming false?

The loop control variable no longer meets the criteria. Signup and view all the answers

Which of the following keywords can be used to exit a while loop?

break Signup and view all the answers

What is the primary purpose of using a switch statement?

To execute code based on the value of a variable. Signup and view all the answers

In the Fibonacci series example, where is the Fibonacci sequence generated?

Using a while loop. Signup and view all the answers

What is the main function of control statements in a program?

To control the execution flow of the program. Signup and view all the answers

In the syntax of an if statement, what follows the 'if' keyword?

A logical expression. Signup and view all the answers

What does the else block do in an if-else statement?

It executes whenever the if statement evaluates to false. Signup and view all the answers

Which of the following is a correct example of an if-else statement?

if (x > y) { z = x; } else { z = y; } Signup and view all the answers

When would you typically use a switch statement instead of if-else statements?

When dealing with multiple possible values for a variable. Signup and view all the answers

What would be the output of the following code snippet? int a=16; if (a%2==0) { System.out.println('This is an even number'); } else { System.out.println('It is an odd number'); }

This is an even number Signup and view all the answers

Which statement best describes the purpose of the boolean expression in an if statement?

It determines the outcome of the statements that follow. Signup and view all the answers

In the context of control structures, what does the term 'branching' refer to?

Making decisions in the execution flow. Signup and view all the answers

Study Notes

Control Structures

Programs use control statements to manage the order of instruction execution
Control flow depends on data values and conditional logic
Java supports Selection, Repetition, and Branching

Selection (Agarwal & Bansal, 2023)

Selection statements are decision-making tools including if, if-else, and switch
if statement:
- Evaluates a logical expression
- Executes statements if the expression is true
- Syntax: if (boolean-expression) { statements; }
- Example: int a = 16; if (a % 2 == 0) { System.out.println("Even number"); }
if-else statement:
- Provides an alternative action if the if condition is false
- Executes the else block when the if condition is false
- Syntax: if (boolean-expression) { statements; } else { statements; }
- Example: if (aNum1 > aNum2) { aMax = aNum1; } else { aMax = aNum2; }
switch statement:
- Easier for multiple possible values
- Compares a variable against a list of constants
- case constants must match the variable type
- break exits the switch construct
- default handles unmatched cases
- Syntax: switch (variable-name) { case exprsn1: statements; break; case exprsn2: statements; break; default: statement; }

Repetition (Agarwal & Bansal, 2023)

Loops repeatedly execute a block of code
while loop:
- Executes a block as long as a condition is true
- Syntax: while (boolean-expression) { statement; }
- Example: int i1 = 1, i2 = 1; System.out.println(i1); while (i1 <= i2) { i2 += i1; i1 = i2 - i1; System.out.println(i1); }
do-while loop:
- Executes a block at least once, then repeats while a condition is true
- Syntax: do { statement; } while (expression);
- Example: int j = 1; do { System.out.println(j); j++; } while (j <= 10);
for loop:
- Useful for loops with a predetermined number of iterations
- Syntax: for (initialization; test-expression; increment/decrement) { statement; }
- Example: int invar; for (invar = 1; invar <= 10; invar++) { System.out.print(invar*invar); }

Branching (Agarwal & Bansal, 2023)

Statements that alter program flow
break statement:
- Exits the innermost loop or switch statement
- break label; exists an outer loop
- Example: for (int i = 1; i <= range; i++) { if (i == 5) break; System.out.println(i); }
continue statement:
- Skips the rest of the current loop iteration
- Resumes with the next iteration
- Example: int i = 1; while (i <= 10) { i++; if (i == 5) continue; System.out.println("i="+i); }
return statements:
- Ends a method's execution
- Returns a value to the calling method
- Example: public static int square(int a) { return (a * a); }

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Description

Test your knowledge on control structures in Java, focusing on selection statements like if, if-else, and switch. This quiz will help reinforce your understanding of how these control mechanisms dictate the flow of a program's execution.