Chapter 4 Selection Control Structure PDF

Chapter 4 Selection Control Structure Topics of discussion : i. how to write pseudocode for selection structure ii. How to draw flow chart for selection structure iii. Solve selection problem using Java 2 Relational Operators...

Chapter 4 Selection Control Structure Topics of discussion : i. how to write pseudocode for selection structure ii. How to draw flow chart for selection structure iii. Solve selection problem using Java 2 Relational Operators 3 Conditional Operators Conditional operators can be used to evaluate complex conditions as a whole 4  Logical Operators Table 4-1 Conditional logical AND && Table 4-2 Conditional logical OR || Table 4-3 Logical NOT 5 Evaluate the following Boolean expression i. 2015 >= 2014 ii. !(12 < 6) iii. 8 != 8 iv. int a = 4, b = 5, c = 6; a < b || b >= c b < = c && c == 6 6 Problem # 1 7 Phase 1 : Problem Analysis Input Process Output base area ← 0.5 * base * height message height IF area > 100 THEN Display “This is a BIG triangle” ELSE Display “This is a SMALL triangle” 8 Phase 2 : Program Design Find_big_triangle Prompt height , base Get height , base area ← 0.5 * base * height IF area > 100 THEN Display “This is a BIG triangle” ELSE Display “This is a SMALL triangle” END IF END 9 Simple if syntax Syntax: if (boolean expression) statement(s); Where the boolean expression must be enclosed by the pair of bracket, ( ). 10 if … else Syntax It is often necessary to execute a statements if a particular condition is true, and another different statement or statement block if the condition is false. In Java we did it with the keyword else. Syntax: if ( boolean expression ) statement(s); else statement(s); 11 Nested if It is possible to nest one if statement inside another. Syntax: if ( boolean expression ) statement(s); if ( boolean expression ) statement(s); 12 The case structure The case structure in pseudocode is another way of expressing a linear nested IF statement It can be translated into many high-level languages Makes pseudocode easier to write and understand The word CASE OF and END CASE serve to identify the structure Eg : CASE OF record_code ‘A’ : increment counter A ‘B’ : increment counter B ‘C’ : increment counter C END CASE 13 Switch statement (case) Another way of doing the if…else statement is by using the switch command. This is a better way of doing if … else if it involves a complex nested if… else statement. Syntax: switch( variable ) { case value1: statement(s); break; case value2 : statement(s); break; default : statement(s); } 14 Switch statement (case) Another way of doing the if…else statement is by using the switch command. This is a better way of doing if … else if it involves a complex nested if… else statement. Syntax: switch( variable ) { case value1: statement(s); break; case value2 : statement(s); break; default : statement(s); } 15 Create a Lesson class. This class offers three lessons; Swim, Snorkel and Dive. Each lesson is divided to three skill levels; Beginner, Intermediate and Advanced. Prompt the user to choose a lesson and enter a skill level. Fees for each lesson will be calculated based on lesson and skill levels as follows: Display total fees for each lesson. Test your program with different lessonLesson and levelLesson Price (RM) ID 1 Swim 50 2 Snorkel 25 3 Dive 100 Level ID Level Price (RM) B Beginner + 10 I Intermediate No extra charges A Advanced - 15 16