Understanding Java Programming Control Structures

1. Announcements • Quiz 1 Posted on blackboard • Quiz 1 Handed Back (and Gone Over) Next Monday • “Just a Quiz” • 5% of Final Grade • Exam 1 is 10% of Final Grade

2. 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

3. 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; statement; }

4. Conditional Operators • Relational Operators: < , > , >= , <= • Equality Operators: == , !=

5. Comparing Strings • Cannot use Equality Operators • Use .equals() instead: String myString; … if (myString.equals(“Hello”) ) System.out.println(“Well, Hello to you too!!”);

6. Selection Examples int age; char grade; String firstName; //Code to assign to age, grade, and firstName 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!” ); if (firstName.equals(“Jon”)) System.out.println(“Thanks, Jon!” );

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

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

9. 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