Question

Code A: var x = 10; y = --x + 1;
alert(y);
Code B: var x = 10;
y = x-- + 1;
alert(y);
What is the output for code A and B?
a)10,11
b)10,10
c)11,10
d)11,11
 

Answer 1

Answer:-10,11

Answer 2

JavaScript programs may generate unexpected results if a programmer accidentally uses an assignment operator (=), instead of a comparison operator (==) in an if statement.

This if statement returns false (as expected) because x is not equal to 10:

Addition is about adding numbers.

Concatenation is about adding strings.

In JavaScript both operations use the same + operator.

Because of this, adding a number as a number will produce a different result from adding a number as a string: