Java for Beginners: Mastering the Fundamentals of Programming, Schemes and Mind Maps of Computer science

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Java for

Beginners

All the basics knowledge needed for becoming a programmer

Variables

 - Variables are the way the program stores the informations.  These informations can be Input Data, Output Data or a Support Variable that we use to keep data while the program is doing other operations.

Example

10 X Variable X

stores 10

11 Y Variable Y

stores 11

Operatios

 - All basics mathematical operations can be performed in Java(+ - / *).  - Advanced operations can be used adding libraries

Example

 - calculator uses numbers and the operation we want to perform  ‘11’ ‘+’ ‘12’  - The result of the operation  ‘33’

Notice

 - Java is a typed language every variable can have only 1 type, which means that can store only a particular kind of data  Es:  int -> the variable can store only integer numbers (1,2,3 etc)  char -> the variable can store only charcacters (a,b,c,d, etc)

FlowChart Diagram

 - We use a flowchart before starting code so we have a better understanding of the sequence of operation we want the code to perform.

Int x;

Our Flowchart

X is an integer variables and stores 10

Y is an integer variable and stores 12

Output we give the result of x+y as output

Int x= 10;

Int y= 12;

x+y;

Input and Output

 - Data Input is an information (number, character, string, anything) that we give to our code in order to do the operation (operations) we want to perform.  - Data Output is the result of the operation (operations) that were performed by the code.

Example

 - Input for the calculator are numbers and the operation we want to perform  ‘1’ ‘+’ ‘2’  - The output is the result of the operation  ‘3’

Send Input from Keyboard

 Scanner console = new Scanner(System.in); -> lets the data inserted from console go to code  int x = console.nextInt(); -> saves the integer in the variable X that sent by pressing “Enter”