Alphabet Pattern ABCDE to E in PHP

Beginner
⏱️ 6 min read
📚 Updated: Aug 2025
🎯 2 Code Examples
Increasing start
Alphabet pattern output ABCDE, BCDE, CDE, DE, E in PHP programming

What You'll Learn

This PHP program prints a triangle where each row starts one letter later (A, then B, then C...) while the end letter stays the same (E for 5 rows).

For rows = 5, the output is ABCDE, BCDE, CDE, DE, E.

⭐ Pattern Output

When you run the program with rows = 5:

Output
ABCDE
BCDE
CDE
DE
E
1

Complete PHP Program

Fixed rows = 5 version:

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

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

for ($i = 0; $i < $rows; $i++) {
    for ($j = $i; $j <= $end; $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

Start index increases each row

Row $i starts at index $i, so the first letter shifts from A to B to C, and so on.

Left edge
3

End index stays fixed

$end = $rows - 1 (E for 5 rows). The inner loop prints from $i to $end, so every row ends at the same letter.

Fixed end
=

Shrinking rows

Total letters printed are 5+4+3+2+1 = 15 for 5 rows, which is n(n+1)/2 in general.

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');
$end = $rows - 1;

for ($i = 0; $i < $rows; $i++) {
    for ($j = $i; $j <= $end; $j++) {
        echo $alpha[$j];
    }
    echo PHP_EOL;
}

💡 Tips for Enhancement

Try These

  • Compare with Program 5 (same widths, but each row starts from A)
  • Switch to lowercase using range('a', 'z')
  • Print only odd-length rows for another variation
  • Right-align rows with leading spaces
  • Choose a different end letter by setting $end manually

Avoid

  • Using <br> in CLI examples (use PHP_EOL)
  • Allowing $rows > 26 without handling wrap-around
  • Off-by-one mistakes in the inner loop bound ($j <= $end)
  • Mixing HTML output with CLI output without intent

Key Takeaways

1

Outer loop controls the starting letter; inner loop prints up to a fixed end letter.

2

Line lengths shrink by one each row: n, n-1, ..., 1.

3

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

❓ Frequently Asked Questions

Program 5 prints prefixes from A (ABCDE, ABCD, ...). This program shifts the start letter each row (ABCDE, BCDE, CDE, ...), while the end letter stays fixed.
Yes. Set $end = 25 (Z) and keep $rows small enough so $i never exceeds 25.
It’s O(n²) for n rows, because the program prints 1+2+…+n letters in total.

Next: PHP Alphabet Pattern 7

Continue to Program 7 for the next alphabet pattern in PHP.

Program 7 →
Did you know?

This pattern keeps the right edge fixed while the left edge moves right each row — a useful idea for many “sliding window” style patterns.

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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