• Learned about 3 primitive types
    • int
    • double
    • boolean
    • The 3 types on the exam
  • Learned how to declare, initialize, and change the value of a variable
  • Learned about operators and casting
  • Learned about range of possible integer values

Concepts: 1.7.1

  • Compiler
    • Software to translate source code into something which can be run by a computer
  • Compiler/Syntax Error
    • An error found during compilation
  • Main method
    • The method which Java executes on runtime
  • Variable
    • A name associated with a memory location
  • Variable declaration
    • Specifying the type and name for a variable
    • Sets aside memory for a variable of that type
    • Associates the name with a memory location
  • Variable initialization
    • Giving a value to a variable for the first time
  • data types
    • determines the size of memory reserved for a variable
    • int, double, boolean
  • integer
    • whole number
    • 2, -3, etc.
  • boolean
    • An expression of true or false
  • camelCase
    • A variable naming scheme
    • appending words together, making the first letter of every word after the first uppercase
    • leftMotor1, getRequestQueue, hasAnswer
  • Casting
    • Changing the type of a variable using
    • (int) 1.2, (char) 33
  • Operator
    • Common mathematical symbols
    • +, -
  • Compound assignment/shortcut operators
    • Operators like x++; to shorten longer common expressions
    • x++ -> x = x + 1
  • modulo
    • returns the remainder of one number divided by another
    • %
  • arithmetic expression
    • sequence of operands and operators in a calculation
    • 3 * (2 + x)
  • operator precedence
    • The order of operations
    • *, / and % come before + and -

Keyword summary: 1.7.2

  • boolean
    • datatype for a variable which can be only true or false
  • double
    • datatype for a variable which is a decimal number
    • 3.68
  • int
    • datatype for a varible which is an integer number
    • 3
  • System.out.print()
    • Prints the arguments provided to stdout
  • System.out.println()
    • Same as System.out.print(), but appends a newline to the end of the output
  • =
    • assigns the value on the right to the variable on the left
  • *, /, %, +, -
    • arithmetic operators

Vocabulary practice: 1.7.3

No real notes, just complete the activities

Common mistakes: 1.7.4

  • Java is case sensitive
  • Forgetting to specify a type during variable declaration
  • Forgetting to declare a variable
  • Using the incorrect variable name
  • Using the incorrect type for a variable
    • Integer types give integer results!
      • 1/3 is 0!
  • Using == to compare doubles
    • Doubles are an approximation and are generally weird
  • Assuming a value like 0 will be smaller than other ints
    • integers can be negative!