Diamond Number-Star Pattern (Initialized)

Understanding the Problem

The goal is to print a diamond-shaped pattern where numbers are printed in increasing order in the upper half and then decreasing order in the lower half. Each number is followed by a star except for the last number in each row. The pattern starts from a specified initialized number.

Pattern Explanation

The pattern consists of two halves: the upper half where numbers increment and the lower half where numbers decrement.

2
3*3
4*4*4
3*3
2
            

Observations:

• The pattern consists of 5 rows.
• Numbers increment from 2 to 4 in the upper half.
• Each number is followed by a '*', except the last number in each row.
• The lower half mirrors the upper half, decrementing from 3 to 2.

Algorithm

The pattern follows these steps:

1. Initialize a variable to determine the starting number (N).
2. Loop through rows from 0 to (N - 2) to print the upper half of the diamond.
3. For each row, calculate the current number as (N + row).
4. Loop through columns (up to the current row number + 1) and print the current number.
5. Print the number followed by '*' except for the last number in the row.
6. After completing the upper half, loop through rows from (N - 2) down to 0 to print the lower half of the diamond.
7. Repeat steps 3 and 4 for the lower half.
8. Move to the next line after printing each row.

Method 1: Using Nested Loops

This method uses two loops to print the pattern.

public class DiamondNumberStarPatternInitialized {
    public static void main(String[] args) {
        int n = 2;  // Starting number for the diamond pattern
        int rows = 3;  // Number of rows in the upper half

        // Loop to print the upper half of the diamond
        for (int i = 0; i < rows; i++) {  // Loop for each row
            int currentNumber = n + i;  // Calculate the current number
            for (int j = 0; j <= i; j++) {  // Loop for each column in the current row
                System.out.print(currentNumber);  // Print the current number
                if (j < i) System.out.print("*");  // Print '*' if not the last number in the row
            }
            System.out.println();  // Move to the next line after each row
        }

        // Loop to print the lower half of the diamond
        for (int i = rows - 1; i > 0; i--) {  // Loop for each row
            int currentNumber = n + i - 1;  // Calculate the current number
            for (int j = 0; j < i; j++) {  // Loop for each column in the current row
                System.out.print(currentNumber);  // Print the current number
                if (j < i - 1) System.out.print("*");  // Print '*' if not the last number in the row
            }
            System.out.println();  // Move to the next line after each row
        }
    }
}
            

Output:

2
3*3
4*4*4
3*3
2