Hi folks,

I hope you enjoyed my last 3 lessons.

I didn't hear questions from you yet.
I don't think that everything 100% understood in my lessons.
so, Where are the questions?

I hope to hear you soon.

Download this lesson & Enjoy it.

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Senior MQL programmer:
www.xpworx.com/custom.htm

I want to ask about arithmetical operators.

1. It is written the following:
A = B + C, with description that add A to B and assign the result to C.
Is it mistake?
The same with A = B - C.

2. And I do not understand A = A % C, with description: A is remider of division of B on C(ex: 10%2 will produce 0).
I simple do not understand 10 % 2 = 0 and 10 % 3 = 1.
May you explain? :confused:

3. It was mentioned that we can not write as:
A=(B++)*5
we must write: :confused:
A++;
B=A*5


May be the following:
B++;
A=B*5

And the other 3 questions.

1. May you explain
A %= B;
Because I do not understand A = A % B
as well.

2. And
A >>= B
Is it
A is greater or equal B ?

3. A += B
it is A = A + B
isn't it?

It’s a mistake. It would be:
A = B + C; "Add B to C and assign the result to A."
A = B - C; "Subtract C from B and assign the result to A."
I have updated the lesson , please donwload it



The remainder operator works by dividing the first number by the second number for the first integer results and then returns the remaining number.

For example:
10%5=0
This is because if you divide 10 by 5 you will get 2 and there no remaining value, so the remainder is 0.
10%8=2
This is because if you divide 10 by 8 you will get 1 (1*8=8), so the remainder is (10-8 = 2).
100%15=10
This is because if you divide 100 by 15 you will get 6 (6*15=90), so the remainder is (100-90=10).
What about 6%8?
It will be 6 because if you divide 6 by 8 you will get 0 (8*0=0), so the remainder is (6-0=6).

The rule is "You can’t combine the increment and decrement operator with other expressions.".

So you can't write:
A=(B++)*5;
or
B=(A++)*5;

But you can write:
A++;
B=A*5;
And
B++;
A=B*5;

How is it work?
Let’s take a live example:
int A=1; //set A to 1
int B;
A++; //increase A by 1, now A=2
B=A*5 //which means B=2*5

__________________
Hope it helps !
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Senior MQL programmer:
www.xpworx.com/custom.htm

A %= B; means A = A % B;
Let’s assume that A = 10 and B = 4 then
A=10%4; //which will produce 2, so now A=2.


No, ">>=" is the Left Shift Assignment operator which shifts the bits of the left hand value left by the number of bits specified in the right hand value. (You will rarely use this operator).

The Greater Than or Equal operator is ">=" (only one Angle bracket).


Yes, A += B; is equal to: A = A + B; and means Add B to A and assign the result to A.
For example if we assumed A=5 and B=10 then:
A+=B will equal to A=10+5 then A=15 now.

__________________
Hope it helps !
Coders' Guru
Senior MQL programmer:
www.xpworx.com/custom.htm

Left shift is not a very interesting operation for traders.

It's a binary operation used for system computing.

For example if you have 32 (In binary = 00100000), and Left Shift it ... you get 00010000 (Move the numbers an item to the left). So ... you would get 16.

As binary is a power of 2.

Left Shift .... is very similar to divide a number by 2
Rigth Shift is very similar to multiply a number by 2.

I tell 'very similar' because according to the way of store numbers and store the sign of the number ... it's not exactly the same.

Anyway, you will never use it.

Operator % = Remainder

Description taken from wikipedia.
The remainder for natural numbers

If a and d are natural numbers, with d non-zero, it can be proved that there exist unique integers q and r, such that a = qd + r and 0 ≤ r < d. The number q is called the quotient, while r is called the remainder. The division algorithm provides a proof of this result and also an algorithm describing how to calculate the remainder.



Examples

• When dividing 13 by 10, 1 is the quotient and 3 is the remainder, because 13=1×10+3.
• When dividing 26 by 4, 6 is the quotient and 2 is the remainder, because 26=6×4+2.
• When dividing 56 by 7, 8 is the quotient and 0 is the remainder, because 56=7×8+0.

Ok. Now I understand.
We can not use our simple arithmetical knowledge.

A += B
is the A increasing on B.

A -= B
is A decreasing on B.

A = B%C
is the remainder from dividing B by C.

And I think A /= B
is
A = A / B.

And A = A + B
is valid because it is not arithmetic.
It is logic.

It's arithmetic.

int A=12;
int B=6;

A = A + B; // --> A = 12 +6;

It is arithmetical operations but it is logic.
In arithmetic if
A + B so it should be C already.
It should not be the same A (the same value).

Because if we are increasing A on B assigning the result to A so
A will be increasing on B all the time. Every second A will be increasing on B without any stopping. It means A plus B is equal A (the same A?) so plus B once again (because of A plus B) is equal A (an other A) which should be added to B and so on.

May be during the coding everything will be clear.

But I have a question.
In Relational operators A == Bi;
It means true if A equal B else false.

Is it necessary to have i after B?