How the calculation is done

Question

In java while calculating any complex mathematical operation how do we proceed right to left or left to right?
for example
let initial values if a=2,b=5,c=5 then in the expression
c=++a/b*c-a+++b;
++a evaluated first or ++b also plz give the final values of a,b,and c;
any help will be highly appreciated

Answer 1

There is something known as operator precedence. If you did maths, there is a concept called BDMAS , That is, First preference to brackets, next divide, next multiply, next add and finally subtract.

Modulo comes between Divide and multiply.

And for your second ques,a+++b shoulld be evaluated as a++ + b, start from left to right.

Answer 2

In most programming languages I've ever tried math is done the same as normally:

https://en.wikipedia.org/wiki/Order_of_operations

The important part here is the differences between ++var and var++. ++var is pre-increment style and will evaluate the value as value + 1 (effectively adding 1 to the value before evaluating it), whereas var++ is post-increment and will evaluate the value as it's current value, but then increase it after the evaluation (adding 1 to the variable after evaluating it).

So, in the expression above, if it's as it seems like it should be considering the lexer/parser should start at the left and move to the right when reading the line:

c= ( ++a / b * c ) - a++ + b; // where a = 2, b = 5, c = 5

c = (( ++2 / 5 ) * 5 ) - 2++ + 5 =
(( 3 / 5 ) * 5 ) - 2 + 5 =
(( 0.6 ) * 5 ) - 2 + 5 =
( 0.6 * 5 ) - 2 + 5 =
3 - 2 + 5 =
1 + 5 = 6

And A, B, and C would be: a = 4, b = 5, c = 6

And if it actually is c=( ++a / b * c ) - a + ++b then:

c = (( ++2 / 5 ) * 5 ) - 2 + ++5 =
(( 3 / 5 ) * 5 ) - 2 + 6 =
(( 0.6 ) * 5 ) - 2 + 6 =
( 0.6 * 5 ) - 2 + 6 =
3 - 2 + 6 =
1 + 6 = 7

And A, B, and C would be: a = 3, b = 6, c = 7

I've been up for around 48 hours though, so *please* feel free to point out any errors here.

Edit: forgot to include final values of A, B, C.

Answer 3

only 1 more doubt how to decide that in the expression
........a+++b it is a++ +b or a + ++b