Introduction to OOP: Control Statements

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Questions and Answers

What is the primary purpose of an algorithm in the context of programming?

To describe a step-by-step approach to solve a problem. (correct)

To define the syntax of a programming language.

To optimize the execution speed of the program.

To manage memory usage during program runtime.

In programming, what does 'program control' refer to?

Specifying the order statements are executed (correct)

The debugging process.

The mechanism for controlling hardware components

The process of writing the actual program code

What defines the normal flow of execution in a program before any transfer of control occurs?

Parallel execution

Sequential execution (correct)

Concurrent execution

Random execution

What is the role of pseudocode in software development?

To help in planning the logic of a program using informal language, but not yet actual implementation. (B) Signup and view all the answers

Which general category do 'if' statements, 'while' loops, and 'for' loops belong to?

Control structures (C) Signup and view all the answers

What is a characteristic of pseudocode?

It uses everyday English to describe programming logic. (B) Signup and view all the answers

A well-planned approach in programming should include understanding of what?

The problem and the available building blocks. (C) Signup and view all the answers

What is the main step that should be taken before writing any program?

Have a thorough understanding of the problem and have a carefully planned apporach. (B) Signup and view all the answers

Which control structure executes statements in the order they are written?

Sequence structure (D) Signup and view all the answers

Which of the following is NOT a type of selection statement?

while statement (D) Signup and view all the answers

Which control structure allows a program to perform actions repeatedly?

Repetition structure (C) Signup and view all the answers

Which statement is used to execute a block of code only if a specific condition is true?

if statement (A) Signup and view all the answers

What is the purpose of the `if...else` statement?

To execute one block of code if a condition is true and another if the condition is false (B) Signup and view all the answers

Which Java statement is used to repeat a block of code while a condition is true?

while statement (B) Signup and view all the answers

In a nested if-else structure, what happens if the first `if` condition is false?

The next <code>else if</code> condition is evaluated. (B) Signup and view all the answers

What does the pseudocode `If student's grade is greater than or equal to 60 Print "Passed"` translate to in Java?

<code>if ( studentGrade >= 60 ) System.out.println( "Passed" );</code> (A) Signup and view all the answers

What will be the output of the following Java code if `studentGrade` is equal to 75? `if ( studentGrade >= 90 ) System.out.println( "A" ); else if ( studentGrade >= 80 ) System.out.println( "B" ); else if ( studentGrade >= 70 ) System.out.println( "C" ); else if ( studentGrade >= 60 ) System.out.println( "D" ); else System.out.println( "F" );`

C (A) Signup and view all the answers

Which of the following describes a repetition statement's execution?

Executes repeatedly while a loop-continuation condition remains true. (D) Signup and view all the answers

Study Notes

Course Information

Course Title: Introduction to Object Oriented Programming
Course Code: CO1105
Lecturer: Ghaith Al-Tameemi
Institution: School of Computing and Mathematical Sciences, University of Leicester
Website: https://le.ac.uk/

Lecture 3: Control Statements

Learning Objectives

Learn and use basic problem-solving techniques
Develop algorithms using pseudocode
Use if and if...else statements
Use while repetition statements
Use for and do...while statements
Use switch statements
Use continue and break statements
Use logical operators

Problem Solving (Programming like a Professional)

Thorough understanding of the problem and a meticulously planned approach is essential before coding
Familiarize yourself with program-building blocks and proven construction techniques

Algorithms

Computing problems can be solved by executing a series of actions in a particular order
An algorithm defines the procedure for solving problems through the actions and their order
Program control is the mechanism for specifying the order in which statements/actions are executed in a program

Pseudocode

Pseudocode is an informal language for developing algorithms
It is similar to natural language
Pseudocode helps to "think out" a program
It typically describes the actions, input/output, calculations in a program

Control Structures

Sequential Execution: Statements are executed sequentially; in the order they appear in the code
Transfer of Control: Java statements alter the normal execution flow
Three control structures form all programs
- Sequence structure
- Selection structure
- Repetition structure

Sequence Structure

Computers typically execute instructions sequentially, from top to bottom, unless directed otherwise
Activity diagram displays the sequential structure where two calculations are performed

Selection Structure

Three selection statement types
- if statement
- if...else statement
- switch statement

Repetition Structure

Three looping statement types
- while statement
- for statement
- do...while statement

if Single-Selection Statement

Pseudocode example: If student's grade is greater than or equal to 60, print "Passed"
Java code example: if (studentGrade >= 60) System.out.println("Passed");

if...else Double-Selection Statement

Pseudocode example: If student's grade is greater than or equal to 60, print "Passed"; otherwise, print "Failed"
Java code example: if (grade >= 60) System.out.println("Passed"); else System.out.println("Failed");

A More Complex Example

Demonstrates a multi-level nested if...else structure.

while Repetition Statement

Repeat an action while a condition remains true.
Example: While there are more items on a shopping list, purchase and remove the next item

Example of Java's while statement

Find the first power of 3 larger than 100
Example code: int product = 3; while (product <= 100) {product = 3 * product; }

Block Scope

Counters are defined before repetition statements in a block
Example code: int counter = 0; while (counter < 10) { // do something and increase counter; counter = counter + 1; }

Compound Assignment Operators

Simplify assignment expressions
Example: c = c + 3 can be written as c += 3

Increment and Decrement Operators

Unary increment operator (++) adds 1 to the operand
Unary decrement operator (-) subtracts 1 from the operand
Prefix operations change the variable's value before using it in an expression
Postfix operations change the variable's value after using it

Preincrementing and Predecrementing

Prefix increment/decrement operators increase/decrease the value of a variable before it's used in an expression
Example: int b = ++a;

Postincrementing and Postdecrementing

Postfix increment/decrement operators increase/decrease the value of a variable after it's used in an expression
Example: int b = a++;

Counter-Controlled Repetition with while statement

Example code illustrating a counter-controlled while loop

The for Repetition Statement

Specifies counter-controlled repetition details in a single line
Example Java code
Detailed explanation of the for loop structure

The for and while loops

Equivalence between for and while loops in terms of tasks
Different scenarios when to use for or while loops

The do...while Repetition Statement

Loop body executes at least once before checking the condition
Example code demonstrating the do...while loop

The switch Multiple-Selection Statement

Performs different actions based on the value of an expression
Example code
Definition of the sequence of case labels and default case (optional) for a switch statement

The break Statement

Causes immediate exit from looping or switch statement
Used to escape a loop prematurely

The continue Statement

Skips the remaining statements in a loop and proceeds to the next iteration
Example code demonstrating the continue statement

Logical Operators

Conditional AND (&&/&)
Conditional OR (||/|)
Boolean AND (&)
Boolean inclusive OR (|)
Exclusive OR (^)
Logical NOT (!)

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Description

This quiz focuses on Control Statements covered in Lecture 3 of the Introduction to Object Oriented Programming course. You will test your understanding of problem-solving techniques, pseudocode, and various flow control constructs such as if, while, for, and switch statements. Mastery of these concepts is crucial for effective programming.