The round() function in PHP is used to round a floating-point number to the nearest integer or to a specified number of decimal places.

🔹 Syntax:

round(float $num, int $precision = 0, int $mode = PHP_ROUND_HALF_UP): float

🔹 Parameters:

1. $num: The number you want to round.
2. $precision (optional): Number of decimal digits to round to. Default is 0.
3. $mode (optional): Specifies how rounding should behave (default is PHP_ROUND_HALF_UP).

🔹 Common Modes:

• PHP_ROUND_HALF_UP (default): Rounds halves up (e.g., 1.5 becomes 2)
• PHP_ROUND_HALF_DOWN: Rounds halves down (e.g., 1.5 becomes 1)
• PHP_ROUND_HALF_EVEN: Rounds to the nearest even number (e.g., 1.5 → 2, 2.5 → 2)
• PHP_ROUND_HALF_ODD: Rounds to the nearest odd number (e.g., 1.5 → 1, 2.5 → 3)

🔹 Examples:

1. Basic Rounding:

echo round(3.4); // Output: 3
echo round(3.5); // Output: 4

2. Rounding with Precision:

echo round(3.456, 2); // Output: 3.46
echo round(3.456, 1); // Output: 3.5

3. Rounding with Modes:

echo round(2.5, 0, PHP_ROUND_HALF_UP);   // Output: 3
echo round(2.5, 0, PHP_ROUND_HALF_DOWN); // Output: 2
echo round(2.5, 0, PHP_ROUND_HALF_EVEN); // Output: 2
echo round(2.5, 0, PHP_ROUND_HALF_ODD);  // Output: 3