PHP program to find the perimeter of rectangle

Problem Description

Given the length and width of a rectangle, we need to implement a PHP program to calculate its perimeter. A rectangle is an enclosed two-dimensional figure with 4 sides. The opposite sides are equal and parallel, and the angle formed by adjacent sides is equal to 90 degrees. The perimeter is the sum of all sides; in other words, the perimeter is twice the sum of length and width. In this tutorial, we will learn how to find the perimeter of a given rectangle in PHP using different methods.

Rectangle perimeter formula

The formula for the circumference of the rectangle is as follows:

$${perimeter = 2 × (length and width)}$$

Of:

• Long - Horizontal distance.
• Width - Vertical distance.

Example

Let's understand the problem description with some input and output examples.

Enter

<code>长 = 10 单位
宽 = 5 单位</code>

Output

<code>30 单位</code>

Explanation

Calculate the circumference using the formula: 2 × (length and width).

<code>周长 = 2 × (10 + 5)
= 2 × (15)
= 30 单位</code>

Enter

<code>长 = 20 单位
宽 = 0 单位</code>

Output

<code>0</code>

Explanation

If the length or width of any dimension is zero, the two-dimensional figure does not exist. Therefore, a non-existent rectangular figure has no perimeter.

Enter

<code>长 = 15 单位
宽 = 10 单位</code>

Output

<code>50 单位</code>

Explanation

Calculate the circumference using formula: 2 × (length and width)

<code>2 × (15 + 10)
2 × (25)
50 单位</code>

Method 1: Direct formula method

We use the direct formula method to calculate the perimeter of a rectangle using PHP. The formula for calculating the circumference of a rectangle is: length, width, length, width

Formula for rectangle perimeter = 2 × (length and width). Return the result after calculating the perimeter.

Implementation steps

Accounting the following steps:

• Prefer length and width as input parameters.
• Calculate the circumference of a rectangle using formula: 2 × (length and width)
• After the calculation is completed, print the result.

Example

The following example is an implementation in PHP following the implementation steps discussed above.

<?php
$length = 10;
$width = 5;

// 使用公式计算周长
$perimeter = 2 * ($length + $width);

// 输出
echo "长为 $length，宽为 $width 的矩形的周长是：$perimeter<br>";
?>

Output

<code>长为 10，宽为 5 的矩形的周长是：30</code>

Time complexity: O(1), constant time Space complexity: O(1), constant space.

Method 2: Use the function

We will use a function to calculate the perimeter of the rectangle. The logic and formula for calculating the circumference of a rectangle are the same. We will use a function so that the code can be reused later by simply changing the value.

Implementation steps

Accounting the following steps:

• We create a function to calculate the perimeter, which uses the formula ${2 * ($length $width)}$ to calculate the perimeter of the rectangle.
• We pass the input value length and width.
• Finally, we output the result.

Example

The following example is an implementation in PHP following the implementation steps discussed above.

<code>长 = 10 单位
宽 = 5 单位</code>

Output

<code>30 单位</code>

Time complexity: O(1), a single function call. Spatial complexity: O(1), because the above function only uses some variables.

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