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C

Pattern Programs

Pattern programs build strong control over nested loops, which is a skill used throughout more advanced programming, including grid-based logic and 2D array processing.

Why practice these?

Pattern programs build strong control over nested loops, which is a skill used throughout more advanced programming, including grid-based logic and 2D array processing.

Program 1: Right-Angled Triangle of Stars

java
public class TrianglePattern {
    public static void main(String[] args) {
        int rows = 5;
        for (int i = 1; i <= rows; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

Output:

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

Program 2: Number Pyramid

java
public class NumberPyramid {
    public static void main(String[] args) {
        int rows = 4;
        for (int i = 1; i <= rows; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(j + " ");
            }
            System.out.println();
        }
    }
}

Output:

1 
1 2 
1 2 3 
1 2 3 4

Program 3: Inverted Star Triangle

java
public class InvertedTriangle {
    public static void main(String[] args) {
        int rows = 4;
        for (int i = rows; i >= 1; i--) {
            for (int j = 1; j <= i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

Output:

****
***
**
*

Key Points to Remember

  • Pattern programs almost always use a nested loop — an outer loop for rows and an inner loop for columns.
  • Practicing patterns strengthens the ability to trace through nested loop logic manually, step by step.
  • Common variations include triangles, pyramids, diamonds, and number/character-based patterns.