1 / 40

Warm-Up: Monday, March 24

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 <br> newline t tab \ backslash ’ single quote

lucio
Download Presentation

Warm-Up: Monday, March 24

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. Review PAP Computer Science Cycle 5

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

  4. 7 Mathematical Operators • Addition (+) • Subtraction (-) • Multiplication (*) • Division (/) • Modulus (%) • Increment (++) • Decrement (--)

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

  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() Java Programming: Guided Learning with Early Objects

  7. 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 ex exp(3)  e3  20.0855369232

  8. Math Methods • log(x) – natural logarithm (base e) of x log(2)  ln(2)  0.69314718056 • log10(x) – base-10 logarithm of x log10(100)  log10(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

  9. Math Methods • pow(x,y) – returns xy pow(2,3)  23  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

  10. 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”

  11. 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”

  12. 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

  13. 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”

  14. 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

  15. 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°

  16. IF Statements PAP Computer Science Cycle 5

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

  18. Branching Structures ? NO YES Task A Task B

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

  20. 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

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

  22. 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

  23. 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!”); }

  24. 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.

  25. 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); }

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

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

  28. 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

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

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

  31. 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.

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

  33. 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); }

  34. 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

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

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

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

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

  39. 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.

  40. 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); }

More Related