Reverse Alphabet Pattern (EDCBA to A) in PHP

Beginner
⏱️ 6 min read
📚 Updated: Aug 2025
🎯 2 Code Examples
Decreasing length
Alphabet pattern output EDCBA, DCBA, CBA, BA, A in PHP programming

What You'll Learn

This PHP program prints a reverse alphabet triangle: the first row is the full reverse run, and each next row becomes shorter.

For rows = 5, the output is EDCBA, DCBA, CBA, BA, A.

⭐ Pattern Output

When you run the program with rows = 5:

Output
EDCBA
DCBA
CBA
BA
A
1

Complete PHP Program

Fixed rows = 5 version:

PHP
<?php
$rows = 5;
$alpha = range('A', 'Z');

$high = $rows - 1; // 4 -> 'E'

for ($i = $high; $i >= 0; $i--) {
    for ($j = $i; $j >= 0; $j--) {
        echo $alpha[$j];
    }
    echo PHP_EOL;
}

🧠 How It Works

1

Alphabet array

$alpha = range('A', 'Z'); gives letters A..Z in an array.

Setup
2

Outer loop: starting index decreases

$i counts down from $high to 0, so the first row starts at E, then D, then C, and so on.

Start moves
3

Inner loop prints down to A

for ($j = $i; $j >= 0; $j--) prints letters from the row start down to A.

Reverse
=

Shrinking reverse rows

Row lengths are 5, 4, 3, 2, 1. Total letters are n(n+1)/2, so runtime is O(n²).

2

Variation — User Input (CLI) Version

Read rows from standard input (works when you run the file from terminal using php):

PHP
<?php
echo "Enter the number of rows (max 26): ";
$rows = (int) trim(fgets(STDIN));
$rows = max(1, min($rows, 26));

$alpha = range('A', 'Z');
$high = $rows - 1;

for ($i = $high; $i >= 0; $i--) {
    for ($j = $i; $j >= 0; $j--) {
        echo $alpha[$j];
    }
    echo PHP_EOL;
}

💡 Tips for Enhancement

Try These

  • Compare with Program 6 (forward rows ending at E)
  • Switch to lowercase using range('a', 'z')
  • Add spaces between letters for readability
  • Right-align each row with leading spaces
  • Try printing a continuous descending stream by changing reset logic

Avoid

  • Using <br> in CLI examples (use PHP_EOL)
  • Allowing $rows > 26 without handling wrap-around
  • Using ++ when you want descending letters
  • Mixing HTML output with CLI output without intent

Key Takeaways

1

Outer loop chooses the row start letter (E, D, C, ...).

2

Inner loop prints downward to A, so each row is a reverse run.

3

Total letters are \(n(n+1)/2\), so runtime is O(n²).

❓ Frequently Asked Questions

Program 2 starts each row at the same letter (E for 5 rows) and grows (E, ED, EDC...). This program starts at E and then shifts the row start down each time (EDCBA, DCBA, CBA...).
It’s O(n²) for n rows, because the program prints 1+2+…+n letters in total.

Next: PHP Alphabet Pattern 8

Continue to Program 8 for the next alphabet pattern in PHP.

Program 8 →
Did you know?

This pattern keeps the last letter fixed at A, while the start letter moves toward it each row.

About the author

Mari Selvan M P
Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

  • Experience 12 years building web and cloud systems
  • Focus Full Stack Development, AWS, and Developer Education

I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.

AWS Certified Developer – Associate (Credly)

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