Alphabet Pattern (A to ABCDE) in PHP
What You'll Learn
This PHP program prints a simple alphabet pattern where each row starts at A and grows by one letter.
For n rows, the total printed letters are 1 + 2 + … + n = n(n + 1)/2.
⭐ Pattern Output
When you run the program with rows = 5:
A
AB
ABC
ABCD
ABCDEComplete PHP Program
Fixed rows = 5 version:
<?php
$rows = 5;
$alpha = range('A', 'Z');
for ($i = 0; $i < $rows; $i++) {
for ($j = 0; $j <= $i; $j++) {
echo $alpha[$j];
}
echo PHP_EOL;
}🧠 How It Works
Build an alphabet array
$alpha = range('A', 'Z'); creates an array with letters A to Z, so you can index letters like $alpha[0] = A, $alpha[1] = B, and so on.
Outer loop: one row per $i
for ($i = 0; $i < $rows; $i++) runs once per row. Row $i prints $i + 1 letters.
Inner loop: print A to the row end
for ($j = 0; $j <= $i; $j++) prints letters from $alpha[0] up to $alpha[$i]. Each echo appends a letter on the same line.
Growing alphabet rows
Total printed letters are n(n + 1)/2 for n rows — O(n²) time and O(1) extra space (besides the alphabet array).
Variation — User Input (CLI) Version
Read rows from standard input (works when you run the file from terminal using php):
<?php
echo "Enter the number of rows (max 26): ";
$rows = (int) trim(fgets(STDIN));
$rows = max(1, min($rows, 26));
$alpha = range('A', 'Z');
for ($i = 0; $i < $rows; $i++) {
for ($j = 0; $j <= $i; $j++) {
echo $alpha[$j];
}
echo PHP_EOL;
}💡 Tips for Enhancement
Try These
- Print lowercase letters by using
range('a', 'z') - Start from another letter (e.g.,
'C') and adjust indexing - Reverse each row (ABCDE to A) for another variation
- Add spaces between letters for readability
- Try a centered alphabet pyramid next
Avoid
- Allowing
$rows > 26without handling wrap-around - Mixing HTML line breaks (
<br>) with CLI output unintentionally - Forgetting the newline after each row
- Using magic numbers like
65when'A'is clearer
Key Takeaways
Use nested loops: the outer loop controls rows and the inner loop prints letters.
Row i prints letters from A to the i-th letter (so each row grows by one).
Total printed letters are \(n(n+1)/2\), so runtime is O(n²).
range('A','Z') provides a clean and readable way to map indices to letters.
Clamp user input to 26 rows to stay within A to Z.
❓ Frequently Asked Questions
range('a', 'z') and the same loops.n rows, because the program prints 1+2+…+n letters in total.Next: PHP Alphabet Pattern 2
Continue to Program 2 for the next alphabet pattern in PHP.
In PHP, range('A','Z') returns an array of letters, which makes pattern problems easy to express without manual ASCII arithmetic.
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