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• Data Types

• Declarations

• Expressions

• Data storage

C++ BasicsC++ Basics

Data TypesData Types

Integers – Integers – ordinalordinal

numbersnumbers

Floating – Floating – realreal numbersnumbers

Address – Address – memorymemory

locationlocation

Structured - Structured - aggregatesaggregates

Integer Data TypesInteger Data Types

ccharhar256 possibilities;256 possibilities;enclosed in single quotesenclosed in single quotes

intintno decimal pointsno decimal pointsno commasno commasno special signs ($, ¥, ‰)no special signs ($, ¥, ‰)

010100010010100010

Characters can be treated as integers -- a legacy from C

cout << ‘B’ – 1 << ‘\n’

011100010011100010

010000010010000010

011000010011000010

011101010011101010

Int Data TypesInt Data Types

Int -- Signed vs. UnsignedInt -- Signed vs. Unsigned

shortshort 65,536 numbers 65,536 numbers-32,768 to 32,767-32,768 to 32,767

longlong 4,294,967,296 numbers 4,294,967,296 numbers

2,147,483,648 2,147,483,648

enum – a collection of symbolic related enum – a collection of symbolic related

constantsconstants

* *

Real Number Data TypesReal Number Data Types Floating point numbers:Floating point numbers:

signed or unsigned with decimal pointsigned or unsigned with decimal point

Types: differ in amount of storage space; Types: differ in amount of storage space; varies with machine varies with machine

float (single precision)float (single precision) double double long double long double

Use Use sizeof ( )sizeof ( ) to find amount of storage to find amount of storage space used. See pages 42 - 43 in textspace used. See pages 42 - 43 in text

* * *

Floating pointFloating point numbers:

Data TypesData Types AddressAddress

pointer value is an actual addresspointer value is an actual addressreference - reference - an alias for another an alias for another

variablevariable CONFUSING, don’t use CONFUSING, don’t use (yet)(yet)StructuredStructured

array - an ordered list of like itemsarray - an ordered list of like items strings are a type of an arraystrings are a type of an array

struct – unordered heterogeneous struct – unordered heterogeneous setset

class – the basis of OO in C++ class – the basis of OO in C++

ConstantsConstantsLiteraltyped directly into the program as needed

ex. y = 23.4 pi = 3.1416 Symbolic (Named)Symbolic (Named)

similar to a variable, but cannot be changed similar to a variable, but cannot be changed after it is initializedafter it is initialized

Syntax:Syntax: constconst typetype VAR = value VAR = value Ex:Ex: constconst intint CLASS_SIZECLASS_SIZE = =

87;87; constconst doubledouble PI PI = 3.1416;= 3.1416;

* *

can change

can NOT change

OperatorsOperators

An An operatoroperator is a symbol that is a symbol that

causes the compiler to take an causes the compiler to take an

action.action.

*

Categories:mathematicalassignment

boolean / logicaletc.

Arithmetic OperatorsArithmetic Operators

additionaddition ++

subtractionsubtraction --

multiplicationmultiplication **

divisiondivision //

modulusmodulus ((remainderremainder)) %%

Unary (minus) operatorUnary (minus) operator

x = -3; x = -3;

y = -x;y = -x;

Arithmetic ExpressionsArithmetic Expressions

Syntaxoperand operator operand

ExampleExample 77 ++ 1515 34 34 -- 189 189 92 92 ** 3131

345 345 // 6.02 6.02 86 86 %% 3 3

*

ModulusModulus

12/3 14/3

12%3 14%3

The modulus operator yields the The modulus operator yields the remainder of integer division.remainder of integer division.

* *

43 12 12 0

43 14 12 2

A Glimpse ofA Glimpse ofOperator OverloadingOperator Overloading

Operator overloadOperator overloadUsing the same symbol for more Using the same symbol for more

than than one operation.one operation.

type int / type int9 / 5

operator performs int division

type double / type double9.0 / 5.0

operator performs double division

*

ModulusModulus

The modulus operator yields the The modulus operator yields the remainder of remainder of integerinteger division. division.

18 % 4 is 218 % 4 is 2 13 % 4 is 1 13 % 4 is 117 % 3 is 2 17 % 3 is 2 35 % 47 is 35 35 % 47 is 3524 % 6 is 024 % 6 is 0 24 % 4 is 0 24 % 4 is 0 4 % 4 % 18 is 4 18 is 4 0 % 7 is 0 0 % 7 is 0

12 % 2.5 12 % 2.5 errorerror 6.0 % 6 6.0 % 6 errorerror Requires floating point division, NOT Requires floating point division, NOT

the samethe same

* * *

Mixed-Mode ExpressionsMixed-Mode ExpressionsOperator overloadOperator overload

Same operator will behave Same operator will behave differently differently depending upon the depending upon the operands.operands.

Operands of the same type give Operands of the same type give results of results of that type.that type.In mixed-mode, In mixed-mode, floating point floating point takes takes precedence precedence..

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Integer DivisionInteger Division int a, b;int a, b;

a = 8;a = 8;b = 3;b = 3;cout << “The result is “ << a / b cout << “The result is “ << a / b

<< endl;<< endl;

The result is 2The result is 2

8 / 3 is 2 and not 2.6667The result must be an integer. The result is truncated to 2.

*

Order of OperationsOrder of Operations

8 + 3 * 4 is 8 + 3 * 4 is ??

Show associativity to clarify.Show associativity to clarify.

( 8 + 3 ) * 4 is 44( 8 + 3 ) * 4 is 44

8 + ( 3 * 4 ) is 20 8 + ( 3 * 4 ) is 20Without parentheses,Without parentheses, 8 + 3 * 4 is 20 8 + 3 * 4 is 20

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P E M D A S from left to right

Order of OperationsOrder of Operations

ExpressionExpression ValueValue

10 10 // 2 * 3 2 * 3

10 % 3 - 4 / 210 % 3 - 4 / 2

5.0 * 2.0 / 4.0 * 2.05.0 * 2.0 / 4.0 * 2.0

5.0 * 2.0 / (4.0 * 2.0)5.0 * 2.0 / (4.0 * 2.0)

5.0 5.0 ++ 2.0 / (4.0 * 2.0) 2.0 / (4.0 * 2.0)

15

-1

5.0

1.25

5.25

* * * * *

Evaluation TreesEvaluation Trees

ii

10 / 2 * 3

* *

10 % 3 - 4 / 2

i

ii

5.0 * 2.0 / 4.0 * 2.0

r

r

r

5 * 2 / (4.0 * 2.0)

i

r

r

Evaluation TreesEvaluation Trees

5.0 * 2.0 / 4.0 * 2.0

5.0 + 2.0 / (4.0 * 2.0)

(5 + 2) / (4.0 * 2.0)

i

r

rr

r

r

r

r

r

Those who Those who fail to plan, fail to plan, plan to failplan to fail