Can Anyone clear me please?

Question

<?php
$str="10";
$str="20";
$sum=$str+$str;
echo $sum;
//output is 40 why?
?>

Answer 1

@ therbishal
you created the first variable ($str="10"), but by using the same variable name ($str="20") you have effectively changes the value of $str to 20. so by adding str+str, you get 40. change the name of the second variable to str2. this way it will add together str=10 +str2=20. sum = 30. also, by using quotations on the value of the variable makes the numbers a string.

Answer 2

Thank you@Phi Long Le @Robin

Answer 3

not understand.

Answer 4

it means we can't add strings but string converted into integer.and first value(10) Replace into second value(20). is it?