Apna College Java Basics Lecture

Topics Covered

• Printing Output in Java
• Variables in Java
• Input from the User
• Data Types

Printing Output in Java

• Basic Command: System.out.print() or System.out.println()
  • print() keeps the cursor on the same line
  • println() moves the cursor to the next line after printing
• Example: System.out.println("Hello World");
• Character Escape for New Line: \n
  • Can be used within strings to move to the next line

Variables in Java

• Definition: Containers for storing data values
• Examples:
  • int a = 25;
  • String name = "Tony Stark";
• Variable Characteristics:
  • Variables are defined with a type (e.g., int, String)
  • Their values can change over time

Data Types

• Primitive Data Types:
  • byte, short, int, long (for integers)
  • float, double (for floating-point numbers)
  • char (for characters)
  • boolean (for true/false)
• Non-Primitive Data Types:
  • Customizable, includes Strings, Arrays, etc.
• Memory Allocation:
  • Different data types occupy different sizes in memory

Input from the User

• Using Scanner Class:
  • Import with import java.util.Scanner;
  • Create scanner object: Scanner sc = new Scanner(System.in);
  • Different methods for input:
    • sc.nextInt() for integers
    • sc.nextLine() for strings

Key Concepts and Examples

• Variable Operations:
  • Arithmetic operations can be performed between variables
  • Example: int sum = a + b;
• Output Examples and Exercises:
  • Printing stars in a pattern
  • Calculating arithmetic expressions
• Importance of Fundamentals:
  • Understanding basic concepts is crucial for solving more complex problems later

Exercises

• Write a program to print a pattern of stars
• Calculate sum, difference, and products of two numbers
• Quiz on evaluating expressions with operator precedence

Next Steps

• Further exploration of advanced topics such as loops, data structures
• Practice with more complex coding exercises

Additional Resources

• Refer to lecture notes for extended concepts and additional exercises