Palindromic Alphabet Pyramid in Java
What You’ll Learn
Each row is a palindrome built from two parts: a descending run (i down to B) and an ascending run (A up to i).
This program prints letters with no extra spaces (unlike right-aligned patterns that use a fixed-width grid). Compare program 18 (palindrome with k = i - 1 on one continuous pass).
⭐ Pattern Output
Output for 5 rows:
A
BAB
CBABC
DCBABCD
EDCBABCDEJava Program (Fixed A–E)
Same logic as the reference: two loops per row to build the palindrome.
public class Main {
public static void main(String[] args) {
int i, j;
for (i = 65; i <= 69; i++) {
for (j = i; j > 65; j--) {
System.out.print((char) j);
}
for (j = 65; j <= i; j++) {
System.out.print((char) j);
}
System.out.println();
}
}
}🧠 How It Works
Outer i is the peak letter (ASCII)
i runs 65…69 (A…E). That value is both the highest letter on the row and the pivot between the descending and ascending halves.
Left wing: j from i down while j > 65
System.out.print((char) j) prints i, then i-1, … down to B. Stopping above 65 skips the first A so it can appear once in the next loop.
Right wing: j from 65 up to i
The second loop prints A through i inclusive. Together with the left wing you get an odd-length palindrome such as CBABC when i == 'C'.
First row edge case
When i == 65, the descending loop body never runs; the ascending loop prints only A. That matches the single-letter first line of the sample output.
Odd-length rows
Row length is 2 × (i - 65) + 1. Summing over n rows gives O(n²) characters from two inner passes per outer iteration.
Variation — User Input
Read rows and compute endChar as 'A' + rows - 1. Clamp rows to 1–26.
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of rows: ");
int rows = sc.nextInt();
rows = Math.max(1, Math.min(rows, 26));
char startChar = 'A';
char endChar = (char) ('A' + rows - 1);
for (char i = startChar; i <= endChar; i++) {
for (char j = i; j > startChar; j--) {
System.out.print(j);
}
for (char j = startChar; j <= i; j++) {
System.out.print(j);
}
System.out.println();
}
sc.close();
}
}💡 Tips for Enhancement
Try These
- Insert spaces between letters (then update the output preview)
- Center the pyramid by printing leading spaces based on the widest row
- Validate
rowssoendCharstays withinA…Z
Avoid
- Using
j >= 'A'in the descending loop without removingAfrom the ascending loop - Letting
rowspush output pastZwithout handling it
Key Takeaways
The descending loop stops before A, so the center character is printed once.
Each row is an odd-length palindrome: lengths 1, 3, 5, …
Total characters printed across n rows is n².
O(n²) time for n rows.
❓ Frequently Asked Questions
A. Stopping early prevents a double A in the middle.r (0-based), print (n - r - 1) spaces first.n² characters.More Java alphabet patterns
Palindromic rows are a great way to practice nested loops and loop boundaries.
The first n odd numbers sum to n², which matches the total characters printed across n rows in this pattern.
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