java

• Declaring variables


  Int wholeNumber = 0;

  double realNumber = 0.0;

  String words = " ";

  char charcter = 'a';
• Get info from user

  System.out.println("question to display goes here");

  VariableName = keyboard.nextInt(); keyboard.nextLine()
• Declaring Arrays


  Int [] arrayWholeNumbers = new int [10];

  
  

  An empty array of 10 integers called arrayWholeNumbers

  
  

  Double [] arrayRealNumbers = new double [5];

  
  

  An array called arrayRealNumbers containing 5 empty doubles

  
  

  String [] array words = new string[20];

  
  

  An array of 20 empty strings called arrayWords
• Pre defined arrays declaring

  Int[] listIntNumbers = {7, 5, 4, 3, 2, 1};

  An array of int called listIntNumbers starting with 7,5,4,3,2,1

  
  

  Double [] listRealNums = {0.1, 2.2, 4.5, 3.3};

  An array called listRealNumbers containing 0.1, 2.2, 4.5, 3.3

  
  

  String [] listWords = {"hello", "goodbye", "welcome"};

  The values hello goodby welcome stored in an array of strings called listWords
• Assignment and calculations


  Whole number = 0;

  Whole number = 0

  
  

  Real number = wholenumber /10;

  Real number number equals wholenumber divided by 10

  
  

  Perimeter = 2*(length + breadth);
• Data output to user


  System.out.println("the message you want to be displayed");
• Adding a variable into an output to user

  System.out-printin("The + sign is concatenation in Strings" +

  words + " you can add numbers in as well" + wholeNumber);

  
  

  String outputSentance = "";

  outputSentance = words + "you can Join together strings like this \n";

  
  

  The "/n" adds a new line to the output

  
  

  The outputsentance = output + "new text" concatenates the new text on to the

  ned of output
• Logical operators


  (wholeNumber > realNumber)

  (wholeNumber < realNumber)

  (wholeNumber <= realNumber)

  (wholeNumber >= realNumber)

  (wholeNumber == realNumber) (wholeNumber |= realNumber)

  (words. equals ("Hello" ))

  (I (words. equals ( "Hello")))

  ( (words. equals("Hello" )) && (wholeNumber ›= realNumber))

  ( (words equals ("Bello")) ||

  (wholeNumber >= realNumber)
• Selection simple


  If (mark > 50) {

  System.out.println("you have passed");

  }

  
  

  
  

  If mark is greater than 50 then display you passes end if
• Selection with else


  If (mark > 50) {

  Output = "well done you passed ";

  } else {

  Output = "you have failed";

  }

  System.out.println(output);

  
  

  
  

  
  

  If mark is greater that 50 then

  Display you passed on screen

  Else

  Display you have failed

  End if
• Selection nested


  if (mark > 70) {

  output = "You got an A in the test":

  } else if (mark > 50) {

  output = "Well done you passed";

  } else {

  output = "You have failed";

  }

  System. out. printin(output);
• Fixed loop


  int total = 0;

  for (int index = 0; index < 10; index ++){

  System.out.println("Please enter the score");

  int score = keyboard.nextInt(); keyboard.nextLine();

  total = total + score;

  }

  
  

  
  

  
  

  Set integer total to 0

  Repeat 10 times

  Get integer score from user using keyboard

  Add score to total

  End loop
• Conditional loop


  System.out.printin("please enter the score between 0 and 10");

  double score = keyboard.nextDouble()n keyboard.nextLine();

  while (score < 0 || score > 10){

  System.out.printin("Error: Please enter a score between 0 and 10");

  score = keyboard.nextDouble(); keyboard.nextLine();

  }

  
  

  Get real value from keyboard as score

  While score < 0 or score > 10 loop

  Display error must be between 0 and 10

  Get real value from keyboard as score

  End loop
• Random numbers


  Int random = N5.randomInt(10);

  
  

  Set int random number to a random number between 0 and 10
• Rounding numbers


  AverageAge = N5.roundDp(averageAge, 2);

  
  

  Round averageAge to two decimal places

  
  

  
  

  Int averageAgeint = N5.roundToInt(averageAge);

  
  

  Used to get rid of the .0 at the end of number if required
• Length of string


  String name = "Mr Hendry";

  If (name.length() > 10) {

  System.out.println("that is a long name");

  }

  
  

  
  

  If length of name is more than 10 characters display wow that is a long name

  End if
• Working with arrays


  String [] names = new string [10];

  For (int index =0; index < names.length; index ++){

  System.out.println(" please enter the persons name");

  Names [index]= keyboard.bextline();

  }

  
  

  
  

  
  

  Create an empty array of number of people strings called names

  
  

  Repeat number of people 10 times

  
  

  Get value for for current index of array names from keyboard

  
  

  End loop