Java Variables and Types

Variables and Types

• A variable (like in math) is used to represent a piece of data

  • Just as an equation uses a variable x to symbolize a number, a program uses a variable to symbolize a block of the computer's memory

  • We declare a variable by writing its type, its name, and assigning its value. E.g.

    • Here, a variable of type integer (int) named myInteger is declared and set equal to 5

    		int myInteger = 5;

    • Here, a variable of type String named myString is declared and set equal to "Hello World"

    		String myString = "Hello World!";

  • So what does the computer do with this?

    • The computer takes the values we assign, and stores them in the memory
    • Once in the memory, we can manipulate these values for calculations and much more

  • Most Common Variable Types:

     int
     float
     double
     String
     boolean