In your if() loop, you have a statement, not a boolean.
You have to use two equals signs.
An if loop compares two values, and one equals sign means that A will equal B.
I cannot explain this simpler.

- MenteCode.

if () is not a loop, but a conditional statement, but mentecode is right.
a = b is an assignment, and for historical reasons, you can use an assignment in such conditions, although it works only when a and b are boolean.
The correct way of writing this is:
if (a == b)

Bonus: a shortcut: a = a + 10; can be written as: a += 10;