有时，您希望在满足某些条件时立即退出循环。break 指令从其块中的任意点退出循环，并忽略循环的条件。继续执行循环后的下一语句。您可以将 break 语句与 while、do 或 for 循环结合使用。
string $words[] = {"a","bb","ccc","dddd","eeeee","ffffff"};
string $long = "";
for ($i = 0; $i < size($words); $i++) {
if (size($words[$i]) > 4) {
$long = $words[$i];
break;
}
print($words[$i] + " is too short...\n");
};
print($long + " is the first long word.\n");