🧠 20 Beginner Coding Problems to Build Logic and Confidence
When I first started learning to code, I quickly realized that writing syntax is the easy part. The real challenge is thinking like a programmer.
Logic-building comes from practice, and the best way to practice is by solving small, meaningful coding problems that train your brain to break down problems into steps.
If you already know the basics like variables, loops, conditionals, and functions, this list is perfect for you.
Let’s start simple and gradually move from easy to moderate problems 👇
💡 How to Practice Effectively
Before you dive in:
✍️ Try to solve each problem yourself first before checking the logic.
🔁 Practice dry runs and trace how your program flows.
🧩 Don’t rush! Understanding why something works matters more than how fast you finish it.
💬 Keep notes on new ideas or patterns you discover.
🧩 Easy Level Problems
1. Print “Hello, World!”
Problem: Write a program to print “Hello, World!”.
Logic: The most basic program to verify your coding setup works.
Example Output:
Hello, World!
2. Sum of Two Numbers
Problem: Take two numbers as input and print their sum.
Logic: Input → add → output. Focus on understanding how to read input and display output.
Example:
Input: 5, 3 → Output: 8
3. Even or Odd
Problem: Check if a number is even or odd.
Logic: Use modulus (%) to check remainder when divided by 2.
Example:
Input: 7 → Output: Odd
4. Find Maximum of Two Numbers
Problem: Given two numbers, print the larger one.
Logic: Use if-else or a ternary operator.
Example:
Input: 10, 20 → Output: 20
5. Simple Interest
Problem: Given principal (P), rate (R), and time (T), calculate simple interest = (P * R * T) / 100.
Logic: Apply formula directly.
Example:
Input: P=1000, R=5, T=2 → Output: 100
6. Factorial of a Number
Problem: Find the factorial of a number (n!).
Logic: Multiply all numbers from 1 to n using a loop.
Example:
Input: 5 → Output: 120
7. Multiplication Table
Problem: Print the multiplication table for a given number.
Logic: Use a loop from 1 to 10.
Example:
Input: 5 → Output:
5 x 1 = 5
...
5 x 10 = 50
8. Sum of First N Natural Numbers
Problem: Given n, find the sum of 1 + 2 + ... + n.
Logic: Either use a loop or formula n*(n+1)/2.
Example:
Input: 10 → Output: 55
9. Reverse a Number
Problem: Reverse digits of an integer.
Logic: Extract digits using % 10, build reversed number using loops.
Example:
Input: 1234 → Output: 4321
10. Count Digits in a Number
Problem: Count how many digits are in a number.
Logic: Divide number by 10 repeatedly until it becomes 0, count the steps.
Example:
Input: 12345 → Output: 5
⚙️ Moderate Level Problems
11. Check Prime Number
Problem: Determine if a number is prime.
Logic: Check divisibility from 2 to √n. If divisible, not prime.
Example:
Input: 7 → Output: Prime
12. Find GCD (Greatest Common Divisor)
Problem: Find GCD of two numbers.
Logic: Use Euclidean algorithm. Keep replacing (a, b) with (b, a % b) until b = 0.
Example:
Input: 20, 8 → Output: 4
13. Fibonacci Series
Problem: Print first n Fibonacci numbers.
Logic: Start from 0 and 1. Each next number is the sum of previous two.
Example:
Input: 5 → Output: 0, 1, 1, 2, 3
14. Palindrome Number
Problem: Check if a number reads the same backward.
Logic: Reverse number and compare with original.
Example:
Input: 121 → Output: Palindrome
15. Armstrong Number
Problem: Check if the sum of cubes of digits equals the number itself.
Logic: Extract each digit, cube it, and sum. Compare with original.
Example:
Input: 153 → Output: Armstrong
16. Sum of Digits
Problem: Find the sum of all digits of a number.
Logic: Extract digits using % 10, add, then divide by 10 to remove last digit.
Example:
Input: 1234 → Output: 10
17. Count Vowels in a String
Problem: Given a string, count vowels (a, e, i, o, u).
Logic: Loop through characters and check if they are vowels.
Example:
Input: "hello" → Output: 2
18. Reverse a String
Problem: Reverse a given string.
Logic: Traverse from end to start or use built-in reverse methods.
Example:
Input: "code" → Output: "edoc"
19. Check Anagram
Problem: Check if two strings are anagrams.
Logic: Sort both strings or count character frequency and compare.
Example:
Input: "listen", "silent" → Output: Anagram
20. Find Second Largest Number in Array
Problem: Find the second largest number in an array.
Logic: Keep track of first and second max while traversing.
Example:
Input: [10, 5, 20, 8] → Output: 10
🚀 What’s Next?
If you’ve made it this far, you’ve already built a solid foundation in logical thinking.
Remember, programming isn’t about memorizing syntax, it’s about solving problems step by step.
Try exploring beginner-friendly practice platforms:
Keep coding, keep building 💪
And if you found this helpful, follow along. I’ll soon share a new list of pattern-based problems to level up your thinking even more!
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