🎯 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
.