🧠 Pre DSA Practice Set (Java)

A curated collection of fundamental Java programs designed to strengthen your basics, logic building, and problem-solving skills — the perfect foundation before diving into Data Structures & Algorithms (DSA).

These exercises cover conditionals, loops, functions, and pattern printing, helping you master Java syntax and core programming logic.

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📁 Folder Structure

PRE-DSA-PRACTICE-SET/
│
├── 01basic/        # Basic logic and condition-based programs (33 questions)
│   ├── EvenOddFirst.java
│   ├── Product.java
│   ├── LeapYear.java
│   ├── SimpleCalculator.java
│   └── ...
│
├── 02loop/         # Programs using loops (for, while, do-while)
│
├── 03function/     # Programs using user-defined functions
│
├── 04basic2/       # Advanced logic-based programs (Perfect No., Palindrome, etc.)
│
└── 05pattern/      # 36 pattern problems (stars, numbers, alphabets)
    ├── StarPattern1.java
    ├── StarPattern2.java
    └── ...

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🧩 Topics Covered

🟢 Basics

• Print statements and simple calculations
• Arithmetic operations (product, average, area of circle)
• Conditional statements (if-else, switch)
• Even or odd (multiple approaches)
• Simple calculator using switch
• Leap year check
• Largest among numbers
• Day of week using switch
• Swap two numbers (with & without third variable)

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🔵 Loops

• Print numbers using for / while loop
• Sum and product of natural numbers
• Reverse a number
• Factorial of a number
• Multiplication table
• Keep entering numbers until a condition is met

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🟣 Functions

• Product of two numbers using a function
• Binomial coefficient (nCr)
• Prime number check (optimized)
• Print primes in a range
• Prime factors of a number
• Print first N natural numbers

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🟠 Advanced Basics (Basic2)

• Perfect number check
• Count digits / Sum of digits
• X raised to power Y
• Fibonacci series
• Palindrome number
• Armstrong number
• LCM and HCF
• Convert Binary ↔ Decimal

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🔺 Pattern Programs (05pattern)

Includes 36 pattern problems using nested loops:

• Right-angled & inverted triangles
• Pyramids and diamonds
• Number & alphabet patterns
• Mirror and combined patterns

Each file (StarPattern1.java → StarPattern36.java) demonstrates unique loop logic, helping you master nested iteration and space control.

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🎯 Purpose

This practice set is designed to:

• Strengthen core programming fundamentals
• Improve logical and analytical thinking
• Prepare you for Data Structures & Algorithms (DSA)
• Build confidence in Java syntax & problem solving

After completing these, you’ll be fully ready to tackle Arrays, Strings, Recursion, and beyond.

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🧰 Tech Stack

• Language: Java
• Editor: Visual Studio Code
• Execution: Command line or integrated terminal

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🚀 How to Run

# Step 1: Compile the program
javac FileName.java

# Step 2: Run the compiled class
java FileName

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👨‍💻 Author

Ebadur Rahman 💼 Software Developer | MERN Stack | Laravel | PHP 🔗 LinkedIn

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⭐ Contributions Welcome

You can:

• Fork the repo and solve the same problems in another language
• Add new questions or optimize existing solutions
• Suggest improvements or alternative logic

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📚 Next Steps

Once you complete this set, move on to:

• Arrays & Strings
• Searching & Sorting
• Recursion
• Linked List, Stack, Queue
• Tree & Graph
• Dynamic Programming (DP)

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“Master the basics — everything else becomes easier.”