TYPE CASTING AND OPERATORS

• JAVA IDENTIFIER


  can be a class name, method name, variable name, or label.

  making your code readable and understandable.
• Rules for naming Identifiers in Java:

  • Must begin with a letter, underscore (_), or dollar sign ($).
  • Cannot start with a digit. Can contain letters (a-z, A-Z), digits (0-9), underscores (_), and dollar signs ($) after the first character.
  • Cannot be a reserved keyword. Case-sensitive: Distinct identifiers may vary in case (e.g., myVariable, MyVariable, and myvariable).
  • No length limit, but clarity is recommended.
  • Spaces are not allowed; underscores or camelCase are preferred for readability.
• TYPE CASTING


  refers to converting a value of one data type into another.
• Two types of Type Casting:

  Widening Conversion

  Narrowing Conversion
• Widening Conversion (Implicit Type Casting)


  converting a smaller data type to a larger data type.
• Narrowing Conversion ( Explicit Type Casting )


  This type of casting occurs when you're converting a larger data type to a smaller data type. It might result in loss of data, so it requires explicit casting.
• JAVA OPERATORS


  symbols used to perform operations on variables and values.
• Java operators can be categorized into five categories:

  Arithmetic operators

  Assignment operators

  Comparison operators

  Logical operators

  Bitwise operators
• ARITHMETIC OPERATORS


  used to perform arithmetic operations on variables and data.
• ARITHMETIC OPERATORS

  addition +

  subtraction -

  Multiplication *

  division /

  Modulus %

  Increment ++

  Decrement –
• ASSIGNMENT OPERATORS


  used in Java to assign values to variables.
• ASSIGNMENT OPERATORS

  =

  +=

  -=

  *=

  /=

  %=
• COMPARISON OPERATORS


  used to compare values and determine the relationship between them. (true or false)
• COMPARISON OPERATORS


  • ==
  • !=
  • >
  • <
  • >=
  • <=
• COMPARISON OPERATORS


  used to check whether an expression is true or false.
• COMPARISON OPERATORS

  • && (logical AND)
  • || (logical OR)
  • ! (logical NOT)
• JAVA STRING


  a class in the Java programming language that represents a sequence of characters.
• length()


  Give an exact number of strings starting from 1
• charAt() 


  Give character at a specific index (starts
• substring(int beginIdx)


  Give a substring from the given index
• substring(int beginIdx, intlastIdx)


  Give a substring starting from begin index & ending at the last index
• indexOf() 


  Give the index of the first ask specified substring w/in a string
• startsWith() 


  boolean vName = name.startsWith()

  println(vName) // true if (“Gerry”)

  Check if the string starts with the specified prefix.
• endsWith() 


  Checks if the string ends with the specified suffix.
• toUpperCase() 


  Converts all characters in the string to uppercase.
• toLowerCase()


  Converts all characters in the string to lowercase.
• replace()


  searches a string for a specified character, and returns a new string where the specified character(s) are replaced.