PHP - 加減

Question

我有可能很愚蠢的問題，但我有這樣的代碼：

<?php 
$x=2; 
$y=4; 
print ("iloczyn = ".$x." * ".$y." = ".$x*$y. "<br>"); 
print ("iloraz = ".$x."/".$y." = ".$x/$y. "<br>"); 
print ("suma = ".$x." + ".$y." = ".$x+$y. "<br>"); 
print ("roznica = ".$x." - ".$y." = ".$x-$y. "<br>"); 
?> 

而且它不工作。前兩個，乘法和除法都很好。但加減法不好。 該腳本的結果是這樣的：

iloczyn = 2 * 4 = 8 
iloraz = 2/4 = 0.5 
4 
-4 

任何想法爲什麼？ 在此先感謝！

Answer 1

括號拯救生命：

$x=2; 
$y=4; 
print ("iloczyn = ".$x." * ".$y." = ".($x*$y). "<br>"); 
print ("iloraz = ".$x."/".$y." = ".($x/$y). "<br>"); 
print ("suma = ".$x." + ".$y." = ".($x+$y). "<br>"); 
print ("roznica = ".$x." - ".$y." = ".($x-$y). "<br>"); 

Answer 2

你串聯，所以它們轉換爲字符串。把parens放在身邊，它會正常工作。

$x= 2; 
$y= 4; 
print ("iloczyn = ".$x." * ".$y." = ".($x*$y). "<br>"); 
print ("iloraz = ".$x."/".$y." = ".($x/$y). "<br>"); 
print ("suma = ".$x." + ".$y." = ".($x+$y). "<br>"); 
print ("roznica = ".$x." - ".$y." = ".($x-$y). "<br>");