04. వేరియబుల్స్, 8 ప్రిమిటివ్ డేటా టైప్స్ & మెమరీ మోడల్ (Variables, Primitive Data Types & Memory Model)

public class PrimitiveRangeInspector {
    public static void main(String[] args) {
        System.out.println("==================================================");
        System.out.println("       JAVA 8 PRIMITIVE DATA TYPES TELEMETRY      ");
        System.out.println("==================================================");

        System.out.printf("  %-8s : %d bytes | Range: %d to %d%n", 
                          "byte", Byte.BYTES, Byte.MIN_VALUE, Byte.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %d to %d%n", 
                          "short", Short.BYTES, Short.MIN_VALUE, Short.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %d to %d%n", 
                          "int", Integer.BYTES, Integer.MIN_VALUE, Integer.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %d to %d%n", 
                          "long", Long.BYTES, Long.MIN_VALUE, Long.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %e to %e%n", 
                          "float", Float.BYTES, Float.MIN_VALUE, Float.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %e to %e%n", 
                          "double", Double.BYTES, Double.MIN_VALUE, Double.MAX_VALUE);
        System.out.printf("  %-8s : %d bytes | Range: %d to %d (Unicode)%n", 
                          "char", Character.BYTES, (int) Character.MIN_VALUE, (int) Character.MAX_VALUE);
        System.out.println("  boolean  : 1 bit   | Values: true or false");

        System.out.println("--------------------------------------------------");
        System.out.println("Status: Primitive memory boundaries verified!");
        System.out.println("==================================================");
    }
}

public class ModernVarInferenceApp {
    public static void main(String[] args) {
        System.out.println("--------------------------------------------------");
        System.out.println("       MODERN JAVA 10+ 'var' INFERENCE DEMO       ");
        System.out.println("--------------------------------------------------");

        // Type inferred automatically at compile time
        var projectName = "Hyderabad Metro Smart Ticketing";
        var passengerCount = 450000;
        var ticketPrice = 55.75;
        var isSystemOnline = true;
        var currencySymbol = '₹';

        System.out.println("Project   : " + projectName + " (" + projectName.getClass().getSimpleName() + ")");
        System.out.println("Passengers: " + passengerCount);
        System.out.println("Ticket    : " + currencySymbol + ticketPrice);
        System.out.println("Live Status: " + (isSystemOnline ? "ONLINE" : "OFFLINE"));

        // Calculating total revenue using inferred variables
        var totalDailyRevenue = passengerCount * ticketPrice;
        System.out.printf("Total Est. Revenue: %c %,.2f%n", currencySymbol, totalDailyRevenue);
        System.out.println("--------------------------------------------------");
    }
}

public class PayrollComputationEngine {
    public static void main(String[] args) {
        // Employee Information using accurate primitive types
        int employeeId        = 84201;
        String employeeName   = "సురేష్ వర్మ";
        char performanceGrade = 'A';
        boolean isPfEligible  = true;

        double basicSalary    = 85000.00;
        double hraPercentage  = 20.0; // 20% House Rent Allowance
        double daPercentage   = 10.0; // 10% Dearness Allowance
        double taxRate        = 12.5; // 12.5% Income Tax

        // Financial Computations
        double hraAmount     = (basicSalary * hraPercentage) / 100.0;
        double daAmount      = (basicSalary * daPercentage) / 100.0;
        double grossSalary   = basicSalary + hraAmount + daAmount;
        double taxDeduction  = (grossSalary * taxRate) / 100.0;
        double pfDeduction   = isPfEligible ? (basicSalary * 12.0) / 100.0 : 0.0;
        double netTakeHome   = grossSalary - (taxDeduction + pfDeduction);

        System.out.println("==================================================");
        System.out.println("       ENTERPRISE EMPLOYEE PAYSLIP ENGINE        ");
        System.out.println("==================================================");
        System.out.printf("  Emp ID   : #%d | Name: %s%n", employeeId, employeeName);
        System.out.printf("  Rating   : Grade %c | PF Status: %s%n", 
                          performanceGrade, isPfEligible ? "Enrolled" : "Exempt");
        System.out.println("--------------------------------------------------");
        System.out.printf("  Basic Pay     : ₹ %,10.2f%n", basicSalary);
        System.out.printf("  HRA (20%%)    : ₹ %,10.2f%n", hraAmount);
        System.out.printf("  DA  (10%%)    : ₹ %,10.2f%n", daAmount);
        System.out.printf("  Gross Salary  : ₹ %,10.2f%n", grossSalary);
        System.out.println("--------------------------------------------------");
        System.out.printf("  Tax (12.5%%)  : -₹ %,9.2f%n", taxDeduction);
        System.out.printf("  PF (12%%)     : -₹ %,9.2f%n", pfDeduction);
        System.out.println("--------------------------------------------------");
        System.out.printf("  NET TAKE HOME : ₹ %,10.2f%n", netTakeHome);
        System.out.println("==================================================");
    }
}