Triangular Multiplication Pattern in PHP

Beginner
⏱️ 5 min read
📚 Updated: Aug 2025
🎯 2 Code Examples
Nested Loops
Triangular multiplication number pattern output in PHP programming

What You’ll Learn

How to print a triangular multiplication pattern in PHP using two nested for loops.

Each row i displays products from i*1 to i*i, giving a multiplication-based number triangle.

⭐ Pattern Output

For rows 1 through 10, the pattern looks like this:

Output
1
2 4
3 6 9
4 8 12 16
5 10 15 20 25
6 12 18 24 30 36
7 14 21 28 35 42 49
8 16 24 32 40 48 56 64
9 18 27 36 45 54 63 72 81
10 20 30 40 50 60 70 80 90 100
1

Complete PHP Program

The outer loop picks the row number, and the inner loop prints the row’s multiplication sequence.

PHP
<?php
for ($i = 1; $i <= 10; $i++) {
    for ($j = 1; $j <= $i; $j++) {
        echo ($j * $i) . " ";
    }
    echo PHP_EOL;
}

🧠 How It Works

1

Outer loop (rows)

for ($i = 1; $i <= 10; $i++) controls row number and table base.

Row control
2

Inner loop (columns)

for ($j = 1; $j <= $i; $j++) prints exactly i values in row i.

Column count
3

Multiplication value

Each cell prints $j * $i, producing row-wise multiples of $i.

Cell logic
4

Move to next line

echo PHP_EOL; starts a new row after each inner loop.

Line break
=

Triangular multiplication table

Total terms are 1+2+...+n = n(n+1)/2, so time complexity is O(n²).

2

Variation — User Input (CLI) Version

This version asks the user for number of rows (run from terminal with php):

PHP
<?php
echo "Enter number of rows: ";
$rows = (int) trim(fgets(STDIN));

if ($rows < 1) {
    echo "Rows must be at least 1" . PHP_EOL;
    exit;
}

for ($i = 1; $i <= $rows; $i++) {
    for ($j = 1; $j <= $i; $j++) {
        echo ($j * $i) . " ";
    }
    echo PHP_EOL;
}

💡 Tips for Enhancement

Try These

  • Align columns with str_pad() for cleaner table look
  • Print reverse triangle by counting rows downward
  • Export rows into arrays for further calculations
  • Add color/styling when rendering in HTML context
  • Change formula (e.g., $i + $j, $i - $j) for new patterns

Avoid

  • Wrapping each value in HTML tags in CLI-focused output
  • Skipping input validation for row count
  • Forgetting newline after each row
  • Mixing row and column loop bounds accidentally

Key Takeaways

1

Outer loop decides row number and multiplier base.

2

Inner loop prints values from i*1 to i*i.

3

Total printed values follow triangular count n(n+1)/2.

4

The same nested-loop shape works for many other numeric formulas.

❓ Frequently Asked Questions

Because the inner loop runs while $j <= $i. For $i = 5, it prints $j = 1..5.
Yes. Change the row limit from 10 to 20 (or read it from input).
This tutorial demonstrates algorithmic output. Plain numeric output is cleaner for CLI and easier to test.
O(n²) due to nested loops and triangular number of printed terms.

Explore More PHP Number Patterns!

Keep sharpening nested-loop skills with more sequence and table patterns.

All Number Patterns →
Did you know?

Triangular multiplication patterns are a practical way to visualize both multiplication tables and triangular-number growth in one exercise.

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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