Level 3 Tasks-(Java)

 

🔴 Level 3 – (Logic & Real-Life Simulation)

1. Library Fine System

Story:
Library charges fines for late returns.
Why: Introduces multi-level conditions.
Logic:

• If days late ≤ 7 → fine = 0.
• If ≤ 12 → fine = (daysLate - 7) × 2.
• Else → fine = (daysLate - 12) × 5 + 10.

Code :

import java.util.*;

class LibraryFine {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        System.out.print("Enter days late: ");

        int d = sc.nextInt(), fine = 0;

        if (d <= 7) fine = 0;

        else if (d <= 12) fine = (d - 7) * 2;

        else fine = (d - 12) * 5 + 10;

        System.out.println("Fine = " + fine);

    }

}

Output :

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2. Railway Platform Allotment

Story:
Trains arrive at different times. Railway must plan minimum platforms.
Why: Real-world scheduling logic.
Logic:

• Input: arrival & departure times.
• Sort times.
• Count overlapping trains → max overlap = platforms needed.

Code :

import java.util.*;

class RailwayPlatform {

    public static void main(String[] args) {

        int arr[] = {900, 940, 950, 1100, 1500, 1800};

        int dep[] = {910, 1200, 1120, 1130, 1900, 2000};

        Arrays.sort(arr); Arrays.sort(dep);

        int i=0, j=0, plat=0, maxPlat=0, n=arr.length;

        while (i<n && j<n) {

            if (arr[i] <= dep[j]) { plat++; i++; }

            else { plat--; j++; }

            maxPlat = Math.max(maxPlat, plat);

        }

        System.out.println("Min Platforms Needed = " + maxPlat);

    }

}

Output :

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3. Festival Lottery Draw

Story:
Village fair draws a winner randomly.
Why: Introduces random number generation.
Logic:

• Input: names array.
• Generate random index.
• Print winner = names[randomIndex].

Code :

import java.util.*;

class Lottery {

    public static void main(String[] args) {

        String names[] = {"Ravi","Sita","Kumar","Anu","Priya"};

        Random r = new Random();

        int win = r.nextInt(names.length);

        System.out.println("Winner = " + names[win]);

    }

}

Output :

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4. Exam Marks Analysis

Story:
School wants average marks and topper.
Why: Practice array calculations.
Logic:

• Input: marks array.
• Loop → sum → average = sum / n.
• Track max = topper.

Code :

class MarksAnalysis {

    public static void main(String[] args) {

        int marks[] = {78, 92, 85, 66, 99};

        int sum=0, max=marks[0], topper=0;

        for (int i=0;i<marks.length;i++) {

            sum+=marks[i];

            if (marks[i]>max) { max=marks[i]; topper=i; }

        }

        double avg = (double)sum/marks.length;

        System.out.println("Average = " + avg);

        System.out.println("Topper = Student " + (topper+1) + " with " + max);

    }

}

Output :

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5. Supermarket Bill with Multiple Items

Story:
Supermarket bills customers for multiple items.
Why: Realistic array + multiplication logic.
Logic:

• Input:
  Items = { Rice=50, Oil=120, Soap=40 }
  Quantities = { 2, 1, 3 }
• Total = sum of (price × quantity).

Code :

class SupermarketBill {

    public static void main(String[] args) {

        String items[] = {"Rice","Oil","Soap"};

        int price[] = {50,120,40};

        int qty[] = {2,1,3};

        int total=0;

        for (int i=0;i<items.length;i++) {

            int amt = price[i]*qty[i];

            System.out.println(items[i]+": "+qty[i]+" x "+price[i]+" = "+amt);

            total+=amt;

        }

        System.out.println("Total Bill = " + total);

    }

}

Output :