1. Selection (if-then-else) Programming Has 3 Types of Control: Sequential (normal): Control of Execution Proceeds One after the Other Selection (if-then-else): Control Proceeds Dependent on Conditions Iteration (looping): Control Repeated until Condition Met

2. JAVA if Statement Syntax Syntax if ( condition ) statement ; If Condition Is True, Statement Is Executed If Condition Is False, Statement Is Not Executed If Multiple Actions Are Required for Statement, a Compound Statement Must Be Used: if ( condition ) { statement ; }

3. Conditional Operators Relational Operators:, >=, <= Equality Operators: ==, !=

4. Selection Examples if (age < 30) System.out.println( “You are very very Young”); if (grade == ‘A’) System.out.println(“Congratulations!” ); if (grade != ‘F’) System.out.println(“You passed!” );

5. else Statement Syntax: if ( condition ) { statement(s) ; //condition true } else { statement(s) ; //condition false }

6. if-else Example if (myGrade >= 60) { System.out.println(“You passed!” ); } else { System.out.println(“How about them Cubs?” ); }

7. Compound Statements Compound Statement: One or More Statements within a Set of Curly Braces Must Use Compound Statement if More than One Statement Is Supposed to be under Control of if or else Conditional Include Curly Braces after if so if other Statements Are Added in Future, Curly Braces Are Already There

8. Nested if Statements if (myGrade >= 80) if (myGrade >= 90) System.out.println(“You have an A!” ); else System.out.println(“You have a B!” ); else System.out.println(“We’ll give you a C.” );

9. if / else (Cascaded) Sequence of if / else Statements Example: if (myGrade > 90) System.out.println(“You have an A!” ); else if (myGrade > 80) System.out.println(“You have a B!” ); else if (myGrade > 70) System.out.println(“You have a C!” ); else System.out.println(“Oh-oh!” );

10. Boolean Type A Boolean Value Is One of Either “True” or “False” In JAVA, Type boolean Example: boolean done = false;... if (currentLetter == ‘Z’) done = true;... if / else Conditionals Must Evaluate to True or False, and Are Therefore Called Boolean Expressions

11. Logical Operators A Logical Operator Is One Used to Further Specify True or False in an Expression Connects Two or More Expressions Together && Is Logical “AND” || Is Logical ‘OR” &&: Both Operands Must Be True for Entire Expression to Be True ||: Only One (or Both) of the Operands Must Be True for Entire Expression to Be True

12. Logical Operators if (numStudents > MIN && numStudents < MAX) classRun = true; if (numStudents > MAX || numInstructors == 0) classRun = false;

13. Operator Precedence () ! (not) *, /, % +, -, >= (Relational Operators) ==, != (Equality Operators) && (Logical AND) || (Logical OR) = (ASSIGNMENT)

14. Order of Operations Precedence: Level of Importance of Operations Multiplicative Operators Have Higher Precedence than Additive Operators: *, /, % Higher +, - Lower Associativity: Order of Operation for Equal Level Precedence Most Operators Have Left-to-Right Associativity Use Parentheses to Force Differing Precedence of Operations

15. Multiple Logical Operators if ( num1 > MAX || num2 == 0 && num3 == 0) System.out.println(“ num1 is MAX or something is 0”); System.out.println(“ I think…..” );

16. Switch Statements Also Called Switch/Case Statement Just Case in Other Languages Selects Among Several Different Actions Can Only Select from Integer or Character If an Integer Value Is Matched, Statements under Control of that Case Block Are Executed

17. Switch/Case Example int numPassengers; System.out.print(“ Enter Passengers: “); numPassengers = scan.nextInt(); switch(numPassengers) { case 2: rate = BASERATE * 0.80; break; case 4: rate = BASERATE * 0.75; break; case 5: rate = BASERATE * 0.55; break; default: rate = BASERATE; break; }

18. Switch Case Example char menuItem; String inputS; System.out.print("Enter Menu Selection: “); inputS = scan.next(); menuItem = inputS.charAt(0); switch(menuItem) { case 'O': //Code to Order Something break; case 'C': //Code to Checkout break; default: //Error Code break; }

19. Announcements Quiz 1 This Thursday 25 minutes 5 % of Total Grade Covers Everything through Lecture last Week –All Terms (Underlined Items) –Variable Declaration, Initialization, and Assignment –Constant Declaration –Expressions –Operators –Input (Scanner) and Output (System.out)