# 2.1 Data types and expressions  (Page 5/5)

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`counter = counter + 1;`

can be reduced to

`counter += 1;`

Here is the full set.

 = *= Multyply /= Divide %= Modulus += Add -= Subtract <<= Left Shift >>= Right Shift &= Bitwise AND ^= Bitwise Exclusive OR (XOR) |= Bitwise Ixclusive OR

if expr1 and expr2 are expressions then

expr1 op= expr2 is equivalent to expr1 = expr1 op expr2

## Logical and relational operators

Relational operators

 Operators Meaning Examples > greater than ```2>3 (is 0) 6>4 (is 1) a>b``` >= greater than or equal to ```6>= 4 (is 1) x>= a``` < less than `5<3 (is 0),` <= less than or equal to ```5<= 5 (is 1) 2<= 9 (is 1)``` == equal to ```3 == 4 (is 0) a == b``` != not equal to ```5 != 6 (is 1) 6 != 6 (is 0)```

Logical operators

 Operators Meaning Data types of the operands Examples && logical and 2 logic expressions ```3<5&&4<6 (is 1) 2<1&&2<3 (is 0) a>b&&c= a || x == 0``` ! logical not 1 logic expression ```!3 (is 0) !(2>5) (is 1)```

## Bitwise operators

 Operators Meaning Data types of the operands Examples & Binary AND 2 binary numbers ```0&0 (is 0) 0&1 (is 0) 1&0 (is 0) 1&1 (is 1) 101&110 (is 100)``` | Binary OR 2 binary numbers ```0 | 0 (is 0) 0 | 1 (is 0)1 | 0 (is 0) 1 | 1 (is 1)101 | 110 (is 111)``` ^ Binary XOR 2 binary numbers ```0 ^ 0 (is 0) 0 ^1 (is 1)1 ^ 0 (is 1) 1 ^ 1 (is 0)101 ^ 110 (is 011)``` << Shift left 1 binary number ```a<> Shift right 1 binary number ```a>>n (is a/2n) 101>>2 (is 1)``` ~ One's complement 1 binary number ```~ 0 (is 1) ~ 1 (is 0)~ 110 (is 001)```

## Increment and decrement operators

Incrementing, decrementing and doing calculations on a variable is a very common programming task and C has quicker ways of writing the code. The code is rather cyptic in appearance.

The increment operator ++ adds 1 to its operand while the decrement operator - -subtract 1. We have frequently used ++ to increment variables, as in

```if (c = = ’\n’) ++n;```

The unusual aspect is that ++ and - - may be used either as prefix operators (before the variable, as in ++n) or postfix operators (after the variable, as in n++). In both cases, the effect is to increment n. But the expression ++n increments n before its value is used, while n++ increment n after its value has been used. This mean that in a context where the value is being used, not just the effect, ++n and n++ are different. For example, if n is 5, then

`x = n++;`

sets x to 5 but

`x = ++n;`

sets x to 6. In both cases, n becomes 6.

The increment and decrement operator can only be applied to variables; an expression like (i + j)++ is illegal.

The five operators listed in the following table are used in addressing array elements and members of structures, and in using pointers to access objects and functions.

 Operator Meaning Example Result & Address of &x Pointer to x * Indirection operator *p The object or function that p points to [ ] Subscripting x[y] The element with the index y in the array x (or the element with the index x in the array y: the [ ] operator works either way) . Structure or union member designator x.y The member named y in the structure or union x -> Structure or union member designator by reference p->y The member named y in the structure or union that p points to

## Type conversions

When an operator has operands of different types, they are converted to a common type according to a small number of rules. In general, the only automatic conversion era those that convert a narrower operand into a wider one without loosing information, such as converting an integer into floating point .

If there are no unsigned operands, the following informal set of rules will suffice:

If either operand is long double, convert the other to long double.

Otherwise, if either operand is double, convert the other to double.

Otherwise if either operand is float, convert the other to float.

Otherwise convert char and short to int.

Then if either operand is long, convert the other to long.

A char is just a small integer, so chars may be freely used in arithmetic expressions

## Precedence of operators

Operators listed by type.

All operators on the same line have the same precedence. The first line has the highest precedence.

 Level Operators Associativity 1 () [] . ->++ (postfix) – (postfix) -----> 2 ! ~ ++ (prefix) -- (prefix) - *&sizeof <----- 3 * / % -----> 4 + - -----> 5 <<>> -----> 6 <<=>>= -----> 7 == != -----> 8 & -----> 9 ^ -----> 10 | -----> 11 && -----> 12 || -----> 13 ?: <----- 14 = += -= <-----

Note:associate left to right

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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