Java Output Examples

Java Basics

• String s = "boo" is a string initialization in Java.
• System.out.println(s.charAt(0)); prints the first character of the string s.

MyInputChar Java Program

• MyInputChar is a Java program that demonstrates user input and character manipulation.
• The program uses a Scanner to read user input and then prints the first character of the input.

Flow Control Statements in Java

• Control statements are essential in programming, making up 60-70% of a program.
• They allow for conditional execution of statements based on conditions.
• There are three categories of control statements: if-else, switch, and loops.

Tokens in Java

• Tokens are the smallest elements of a Java program that are meaningful to the compiler.
• Tokens include keywords, identifiers, operators, separators, and literals.
• Example: int num = 5 + 4; is a Java statement with tokens:
  • int is a keyword.
  • num is an identifier.
  • = and + are operators.
  • 5 and 4 are literals.
  • ; and white spaces are separators.

Keywords in Java

• Keywords are reserved words in Java with predefined meanings.
• Examples of keywords include abstract, boolean, byte, case, char, class, continue, default, do, extends, final, float, for, if, implements, instanceof, int, long, native, package, private, public, return, static, super, synchronized, this, throws, transient, void, and volatile.

Identifiers in Java

• Identifiers are names given to programming elements such as variables, functions, and user-defined types.
• Format: [a-zA-Z] [_a-zA-Z0-9]*

If-Else Statements in Java

• If-else statements are used for conditional execution of statements.
• Format: if (Boolean expression) Body of if else Body of else
• Example: if (x < 0) System.out.println("X is negative"); else System.out.println("X is non-negative");

Branching in Java

• Branching is used to execute different statements based on conditions.
• Common mistakes in branching include incorrect indentation and incorrect use of semi-colons.

Decision Making in Java

• Decision making is used to execute different statements based on conditions.
• If-else statements are used for decision making.
• Relational operators are used in decision making.

Output in Java

• Output in Java is achieved using System.out.print() and System.out.println() methods.
• Example: System.out.println("Good-night gracie!");
• Escape sequences are used for formatting output, such as \t, \r, \n, \", and \\.

Java Character Set

• Java character set defines the set of valid characters used to write a Java program.
• The set includes alphabets, digits, special characters, and white space characters.