Warm-Up: Monday, March 24 List as many commands in Java as you can remember (at least 10)

Review PAP Computer Science Cycle 5

Output System.out.print( ) System.out.println( ) Escape sequences \n newline \t tab \\ backslash \’ single quote \” double quote

7 Mathematical Operators Addition (+) Subtraction (-) Multiplication (*) Division (/) Modulus (%) Increment (++) Decrement (--)

Declaring/Initializing a Variable Example 1 int x; x = 5; Example 2 int x = 5;

Java Programming: Guided Learning with Early Objects 6 Input (Read) Statement The Scanner class puts data into variables from the standard input device static Scanner console = new Scanner(System.in); Next input is: Integer: console.nextInt() Double: console.nextDouble() String: console.next() or console.nextLine()

Math Methods abs(x) – absolute value abs(-96.5)  95.6 ceil(x) – ceiling operator ceil(54.13)  55 floor(x) – floor operator floor(54.13)  54 exp(x) – returns e x exp(3)  e 3 

Math Methods log(x) – natural logarithm (base e) of x log(2)  ln(2)  log10(x) – base-10 logarithm of x log10(100)  log 10 (100)  2.0 max(x,y) – maximum of two numbers max(15, 25)  25 min(x,y) – minimum of two numbers min(3, 4)  3

Math Methods pow(x,y) – returns x y pow(2,3)  2 3  8 round(x) – rounds x to the nearest whole # round(34.4)  34 round(34.7)  35 sqrt(x) – square root of a number sqrt(121)  √121  11

String Methods String.length( ) – returns the length of the string (how many letters long it is) String word = “dog”; word.length( )  3 String.toLowerCase( ) – changes all capital letters to lowercase String word = “HAHA”; word.toLowerCase( )  “haha”; String.toUpperCase( ) – changes all lowercase letters to capital letters String word = “kitty”; word.toUpperCase( )  “KITTY”

More String Methods String.charAt(x) – returns the letter at position x in the String String word = “happy”; word.charAt(2)  ‘p’; String.replace(x,y) – replaces each instance of character ‘x’ with character ‘y’ String word = “happy”; word.replace(‘p’,’ r’)  “harry”

indexOf( ) indexOf(char) – returns the index, or list location, of the first instance of letter char String word = “happy”; word.indexOf(‘h’)  0 indexOf(str) – returns the index, or list location, of the first instance of a String str String name = “Alexander”; name.indexOf(“and”)  4 Note: Both of these commands will return -1 if the character or String is not found

String.substring( ) String.substring(x, y) – Converts the characters between list location x of the String (inclusive) and list location y of the String (exclusive) into a new String String word = “Spring Break”; word.substring(0,6)  “Spring” word.substring(7, 12)  “Break” word.substring(3, 9)  “ing Br”

TODAY IF YOU ARE MISSING WORK…USE THIS TIME TO COMPLETE SOME OF YOUR MISSING WORK IF YOU ARE NOT MISSING WORK codingbat.com/java Complete codes within any section (though String-1 will likely be the easiest) 1 ML:A pass per SECTION STAR completed

Warm-Up: Tuesday, March 25 Give an example of a program that would require you to use an IF statement EXAMPLE: Output the phrase “Be sure to wear a jacket” if the temperature is less than 55°

IF Statements PAP Computer Science Cycle 5

IF Statements IF statements are used to add branching structure to your codes They are used to make decisions

Branching Structures ? Task A Task B YES NO

IF Statement: Structure if (condition) { //statements } STATEMENTS ARE ONLY EXECUTED IF THE CONDITION IS TRUE

Conditions Conditions evaluate a state or compare two or more numbers While the code is running If x is greater than y If the remainder is equal to 0 While x + y is less than 7

Conditional Operators Less than (<) Greater than (>) Equal to (==) Less than or equal to (<=) Greater than or equal to (>=) Not equal to (!=)

English to Code x is greater than y x > y x plus y is less than 7 x + y < 7 x is an even number x % 2 == 0 the number does not equal our target number != target

Using Conditions with IF Statements If the temperature is below 55, output that the user needs a jacket if (temp < 55) { System.out.println(“Bring a jacket!”); }

Warm-up: Thursday, Mar 27 Write an IF statement for the following: Given two numbers num1 and num2, output the sum of the numbers ONLY IF the sum is less than 10.

Warm-up: Thursday, Mar 27 Write an IF statement for the following: Given two numbers num1 and num2, output the sum of the numbers ONLY IF the sum is less than 10. double sum = a+b; if (sum < 10) { System.out.println(sum); }

Review: IF Statements Used to add branching structure to codes Make decisions Answer questions if (condition) { //statements; }

Review: Conditional Operators Less than (<) Greater than (>) Equal to (==) Less than or equal to (<=) Greater than or equal to (>=) Not equal to (!=)

IF-ELSE Statements Used for situations with two possible outcomes Noted by the keyword “otherwise” Examples If it’s sunny, wear shorts; otherwise, wear jeans If it’s a weekday, set the alarm for 7:00, otherwise, turn off the alarm

IF-ELSE Statement: Structure if (condition) { //statements; } else { //statements; } *NOTE: There is NO condition after else

Example: IF-ELSE if (weather==“sunny”) { System.out.println(“Wear shorts”); } else { System.out.println(“Wear jeans”); }

EVEN MORE BRANCHING! Sometimes, you need EVEN MORE than 2 outcomes For these situations, you use IF – ELSE-IF – ELSE statements Examples If you like dogs, buy a dog, but if you like cats, but a cat; otherwise, get a different pet. If your number is divisible by 5, output 1, but if your number is divisible by 7, output 2; otherwise, output 0.

IF – ELSE-IF – ELSE Structure if (condition1) { //statements; } else if (condition2) { //statements; } else { //statements; }

Example IF – ELSE-IF – ELSE if (num % 5 == 0) { System.out.println(1); } else if (num % 7 == 0) { System.out.println(2); } else { System.out.println(0); }

ELSE-IF’s You can have as many ELSE-IF’s in an IF statement as you want, but you can only have ONE IF and ONE ELSE

OKAY if ( …) { } else if (…) { } else if (…) { } else { }

NOT OKAY if ( …) { } else if (…) { } else { } else { }

OKAY…but it doesn’t mean the same thing… if ( …) { } if (…) { } else if (…) { } else { }

OKAY…but it doesn’t mean the same thing… if ( …) { } if (…) { } else if (…) { } else { }

Warm-Up: Friday, Mar 28 Write an IF statement for the following situation: Given two numbers, a and b, output the sum; unless the sum is greater than 20, then output the number 20.

Warm-Up: Thursday, Mar 26 Given two numbers, a and b, output the sum; unless the sum is greater than 20, then output the number 20. sum = a+b; if (sum > 20) { System.out.println(20); } else { System.out.println(sum); }