! = Isn't this an inequality symbol? Why multiplication

Question

$sum=1;
     for($i=1;$i<=$name;$i ){
      $sum*=$name[$i];
     echo "{$sname} != {$sum}"; 

提示错误？

Answer 1

! =If you put it in double quotes, wouldn't it just be a string?

Answer 2

The cause of the error has been solved and now I understand! = has no specific meaning, just a symbol

Answer 3

The reason for the error is that the braces after the for loop do not match

Answer 4

That's right

Answer 5

That's not a factorial, it's a statement from echo, so it looks like a factorial after it's output.

Answer 6

var_dump()Try