How to write a unit conversion program using PHP

PHP is a popular programming language that has been widely used in various network application development due to its simplicity and ease of learning. This article will introduce how to use PHP to write a unit conversion program.

Unit conversion is a very basic knowledge point in computer science. By converting a certain quantity into different units, it can help us better understand and compare physical quantities. For example, the speed of sound and light that we often hear, if expressed in different units, is the speed of sound and the speed of light. By converting them into meters per second, you can compare the speeds of the two more intuitively.

In PHP, unit conversion can be achieved through the following steps:

1. Determine the basic quantity of conversion and its unit
2. Define the conversion function
3. Write the output interface, enter the amount to be converted and its unit, and call the conversion function for calculation

The following is an example of PHP unit conversion:

<?php
//定义转换函数
function unit_conversion($value, $from_unit, $to_unit){
    //将各个单位对应到一个数组中
    $units = array(
        &#39;m&#39; => 1,
        'cm' => 0.01,
        'mm' => 0.001,
        'km' => 1000,
        'ft' => 0.3048,
        'yd' => 0.9144,
        'mi' => 1609.34,
    );
    
    //计算转换后的值
    $result = ($value * $units[$from_unit]) / $units[$to_unit];
    return $result;
}

//获取用户输入
$value = $_POST['value'];
$from_unit = $_POST['from_unit'];
$to_unit = $_POST['to_unit'];

//进行单位转换
$result = unit_conversion($value, $from_unit, $to_unit);

//输出转换结果
echo "转换结果：". $result . $to_unit;
?>

In the above example , we first defined a function unit_conversion(), which receives 3 parameters: the value to be converted, the original unit, and the target unit. Inside the function, we use an array to map each unit to a value, and use simple mathematical operations to calculate the converted value.

In the main program, we mainly obtain user input and call the unit_conversion() function to perform conversion. Finally, the converted results are output to the user.

The above is a simple PHP unit conversion program that can be used for the conversion of various physical quantities. During the writing process, we mainly need to pay attention to the conversion relationship of each unit. Through reasonable design and calculation, we can convert different physical quantities into more intuitive and comparable units, making it easier to understand and compare.

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