PHP 自动类型转换和强制类型转换示例

<?php
$a = 2020;
$b = '相信明天会更好';
$c = true;

// 自动类型转换
echo '$a = $a, $b = $b, $c = $c\n';
echo '$a+$c = ' . ($a + $c) . '\n';
echo '$a+$b = ' . ($a + $b) . '\n';

// 强制类型转换
echo '$a = $a, $b = $b, $c = ' . (int)$c . '\n';
echo '$a+$c = ' . ($a + (int)$c) . '\n';
echo '$a+$b = ' . ($a + (int)$b) . '\n';
?>

输出结果为：

$a = 2020, $b = 相信明天会更好, $c = 1
$a+$c = 2021
$a+$b = 2020
$a = 2020, $b = 相信明天会更好, $c = 1
$a+$c = 2021
$a+$b = 2020