Nested If Statements and Comparing Strings ifelseif statements

Nested If Statements and Comparing Strings

if-else-if statements

if it is very cold, wear a heavy coat, else, if it is chilly, wear a light jacket, else, if it is windy wear a windbreaker, else, if it is hot, wear no jacket.

if-else-if Syntax else statements match up with immediately preceding unmatched if if (expression) statement or block else if (expression) statement or block // Put as many else ifs as needed here else statement or block

if-else-if Flowchart

Guided Worked Example Enter your score: 86 Your grade on the assignment is: B

Nested if statements

Nested if Flowchart No Yes Is it cold outside? Wear shorts. No Wear a jacket. Is it snowing? Yes Wear a parka.

Nested if Loan. Qualifier Example No Yes Are you employed? Not qualified No Not qualified A recent graduate? Yes You qualify

Nested if Loan. Qualifier Example Curly braces not required for single statements improve readability watch indentation! if (employed == ′y′) { if (recent. Grad == ′y′) { System. out. println("You qualify for the " + "special interest rate. "); } else { System. out. println("You must be a recent " + "college graduate to qualify. "); } } else { System. out. println("You must be employed to qualify. "); }

if-else Matching This else matches with this if. if (employed == ′y′) { if (recent. Grad == ′y′) { System. out. println("You qualify for the " + "special interest rate. "); } else { System. out. println("You must be a recent " + "college graduate to qualify. "); } } else { System. out. println("You must be employed to qualify. "); }

CS Departmental Scholarship Eligibility No Yes CS major? Not eligible No Not eligible GPA at least 3. 2? Yes Eligible Note: the 3. 2 GPA is just an example and not an actual cutoff used by the department.

Guided Worked Example Are you a CS major? (yes or no): no I’m sorry, you must be a CS major to qualify Are you a CS major? (yes or no): yes What is your GPA: 2. 15 Ineligible due to GPA Are you a CS major? (yes or no): yes What is your GPA: 3. 5 You are eligible for scholarship consideration

Comparing Strings

Comparing Strings name 1 String name 1; ? reference variable "Leslie Knope" name 1 = "Leslie Knope";

Comparing Strings name 1 0 X 0045 String name 1; 0 X 0045 "Leslie Knope" name 1 = "Leslie Knope";

Comparing Strings name 1 String name 1; "Leslie Knope" name 2 Only true if they refer to the same object name 1 = "Leslie Knope"; String name 2; name 2 = name 1; if (name 1 == name 2) …

Comparing Strings name 1 String name 1; "Leslie Knope" name 2 Otherwise it is false even if the strings contain the same characters "Leslie Knope" name 1 = "Leslie Knope"; String name 2; name 2 = "Leslie Knope"; if (name 1 == name 2) …

Comparing Strings name 1 String name 1; "Leslie Knope" name 2 returns true if the strings contain same characters "Leslie Knope" name 1 = "Leslie Knope"; String name 2; name 2 = "Leslie Knope"; if (name 1. equals(name 2)) …

Comparing Strings name 1 String name 1; name 1 = "Leslie Knope"; "Leslie Knope" String name 2; name 2 compares strings but ignores case name 2 = "LESLIE KNOPE"; if (name 1. equals. Ignore. Case(name 2)) … "LESLIE KNOPE"

Comparing Strings returns an integer value indicating the alphabetical ordering of the two strings String name 1, name 2; name 1. compare. To(name 2) name 1 = "Leslie Knope"; name 2 = "Ann Perkins" name 1 = "Andy Dwyer" if name 1 is alphabetically less than name 2 compare. To returns a negative value -4 -3 if name 1 is alphabetically equal to name 2 compare. To returns zero -2 -1 0 1 There is also a compare. To. Ignore. Case if name 1 is alphabetically greater than name 2 compare. To returns a positive value 2 3 4

Guided Worked Example Enter the first name: Connor Enter the second name: Claire The name Claire comes before the name Connor Enter the first name: Connor Enter the second name: Grant The name Connor comes before the name Grant Enter the first name: Grant Enter the second name: Grant The two names are equal!

Reference: Flowcharts adapted from Starting Out with Java by Tony Gaddis Chapter 3 Slides.