Day 1 of #LearnInPublic Java Patterns

Aviral Pathak — Sat, 01 Nov 2025 21:10:27 +0000

🎯 Topic: Rectangular Star Pattern
👨‍💻 Concepts Used: Nested Loops

I learned how to use nested for loops in Java to print shapes.
Outer loop → controls rows
Inner loop → controls columns

Here’s my output for N = 4 👇

* * * *
* * * *
* * * *
* * * *

It looks simple — but understanding how loops nest inside each other really builds logic skills for future problems.

💡 Takeaway: Pattern questions are the best way to train your brain for logical thinking.

class Main {
   static void pattern1(int N)
{
    // This is the outer loop which will loop for the rows.
    for (int i = 0; i < N; i++)
    {
         // This is the inner loop which here, loops for the columns
        // as we have to print a rectangular pattern.
        for (int j = 0; j < N; j++)
        {
            System.out.print("* ");
        }

         // As soon as N stars are printed, we move to the
        // next row and give a line break otherwise all stars
        // would get printed in 1 line.
        System.out.println();
    }
}

    public static void main(String[] args) {

        // Here, we have taken the value of N as 5.
        // We can also take input from the user.
        int N = 5;
        pattern1(N);
    }
}

Approach:
There are 4 general rules for solving a pattern-based question:

We always use nested loops for printing the patterns. For the outer loop, we count the number of lines/rows and loop for them.
Next, for the inner loop, we focus on the number of columns and somehow connect them to the rows by forming a logic such that for each row we get the required number of columns to be printed.
We print the ‘*’ inside the inner loop.
Observe symmetry in the pattern or check if a pattern is a combination of two or more similar patterns.
In this particular problem, we run the outer loop for N times since we have N rows to be printed, the inner loop also runs for N times as we have to print N stars in each row. This way we get a rectangular star pattern (square) with an equal number of rows and columns .

DEV Community: Aviral Pathak

Day 1 of #LearnInPublic Java Patterns