Lecture Ppt 8

8/2/2019 Lecture Ppt 8

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Computer ProgrammingAn Introductory Training


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Schema of Discussion

Logical Operators

The Equality Operator ==

The Logical Not Operator !

The Inequality Operator !=

The Comparison for a Lower Value

When two values of the same type aredistinct, one of them is usually higher

than the other. C++ provides a logicaloperator that allows you to find out ifone of two values is greater than theother. The operator used for this

operation uses the > symbol. Its syntaxis:

Value1 > Value2

Both operands, in this case Value1 and


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The Comparison for aGreater Value >=

The greater than and the equalityoperators can be combined to produce

an operator as follows: >=. This is the"greater than or equal to" operator. Itssyntax is:

Value1 >= Value2

A comparison is performed on bothoperands: Value1 and Value2. If thevalue of Value1 and that of Value2 are

the same, the comparison produces a


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Boolean Variables

The Boolean data type is used todeclare a variable whose value wouldbe set as true (1) or false (0). To declaresuch a value, you use the bool keyword.

The variable can then be initialized witha starting value. The Boolean constant

is used to check that the state of avariable (or a function) is true or false.

You can declare such a variable as:

bool GotThePassingGrade = true;
http://www.functionx.com/cpp/Lesson08.htmhttp://www.functionx.com/cpp/Lesson08.htm


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Boolean Variables

Here is an example:

#include

using namespace std;

int main()

{

bool MachineIsWorking = true;


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Enumerations

An enumeration provides a technique ofsetting a list of integers where eachitem of the list is ranked and has aspecific name. For example, instead ofnumbers that represent players of afootball (soccer) game such as 1, 2, 3,

4, 5, you can use names instead. Thiswould produce GoalKeeper,RightDefender, LeftDefender, Stopper,Libero. The syntax of creating an

enumeration is


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Enumerations

Each name in this list represents aconstant number. Since theenumeration list is created in thebeginning of the program, or at leastbefore using any of the values in thelist, each item in the list is assigned a

constant number. The items arecounted starting at 0, then 1, etc. Bydefault, the first item in the list isassigned the number 0, the second is 1,

etc. Just like in a game, you do not have


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Enumerations

You still can assign any value of yourchoice to any item in the list, or you canset different ranges of values to variousitems. You can create a list like this:

enum Days { Mon, Tue, Wed, Thu, Fri,Sat, Sun = 0 };

Since Sun is No. 0, Sat would be No. 1,Fri would be 2 and so on. On the otherhand, you can set values to your liking.

Here is an example:


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Enumerations

Once the list has been created, thename you give to the list, such asPlayers, becomes an identifier of itsown, and its can be used to declare avariable. Therefore, a variable of theenumerated type would be declared as:

Series_NameVariable;You can declaremore than one variable of such a type.An example of the type of our list of

players would be:


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Enumerations

include


main()

{

enum PizzaSize {psSmall, psMedium,psLarge, psJumbo};


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Enumerations

To assign your own values to the list,you could change the enumeration asfollows:

enum PizzaSize {psSmall = 4,psMedium = 10, psLarge = 16, psJumbo= 24};

To get the starting as you want, changethe enumeration as follows:


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Enumerations

#include


main()

{

enum PizzaSize {psSmall = 4,psMedium, psLarge, psJumbo};


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Enumerations

To assign values at random, you couldchange the list of pizzas as follows:

enum PizzaSize {psSmall = 2,psMedium, psLarge = 14, psJumbo =-5};

This would produce:The small pizza has a value of 2 The

medium pizza has a value of 3 The largepizza has a value of 14 The jumbo pizzahas a value of 5

Lecture Ppt 8

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