apcs lab 4

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Lab 4

Westfield High School

APCS LAB 4

APCS LAB 4

Parameters, apvectors,

structs

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Lab 4


A C++ program# includes //function declarations(with brief comment)

//function definitions (with preconditions and postconditions)

int main()

void function1()

int function2()

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Lab 4


# includes //function declarations int a,b;//function definitions

int main()

void function1()

int function2(int b)int a,c;

int a, c, d;

int a,d,e;

global ‘a’ not accessible here

global variables - accessibleeverywhere (almost)

global ‘a’ not accessible here

global ‘a’,’b’ not accessiblehere

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Lab 4


# includes //function declarationsint a,b;//function definitionsint main()

void function1()

int function2(int b)int a,c;

int a, c, d;

int a,d,e;

How do I refer to the global ‘a’ ?

Why do some functions haveempty parameter lists?

How do I return more than one value?

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Lab 4


functions with no argumentsfunctions with no arguments

void menu()

{

cout << “directions appear here” <<endl;

}

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Lab 4


function overloadingfunction overloading

int max(int a, int b)

{

if (a > b)

return(a);

else

return(b);

}

double max(double a, double b)

{

if (a > b)

return(a);

else

return(b);

}

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Lab 4


Call-by-reference parameters‘remembering’ more than one valueCall-by-reference parameters‘remembering’ more than one value

void swap(int &a, int &b)

{

int temp;

temp = a;

a = b;

b = temp;

}(pg 39)

int max(int a, int b)

{

if (a > b )

return(a);

else

return(b);

}

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Lab 4


#include <iostream.h>

int a=1,

b=2;

void dog (int a,int &b);

int main()

{

cout <<a<<" "<<b<<" "<<endl;

dog(a,b);

cout <<a<<" "<<b<<" "<<endl;

return(0);

}

void dog(int a,int &b)

{

a = 5;

b = 6;

cout <<a<<" "<<b<<" "<<endl;

}

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Lab 4


precondition: what is needed for the function to do its intended task ?

postcondition : what is returned if precondition is satisfied?

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Lab 4


apvectorsapvectors

Quick Reference in Appendix A member functions

• length()• resize()

const reference parameters instead of call by value

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Lab 4


n2

SORTSn2

SORTS

BUBBLE SELECTION INSERTION

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Lab 4


LAB 4 ASSIGNMENTLAB 4 ASSIGNMENT

Sorts (#1)• sortall.cpp, the client program (written)• sorts.h, the function declarations (written)• sorts.cpp, the implementation (YOU MUST

WRITE)

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Lab 4


STRUCTSSTRUCTS

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Lab 4


STRUCTSSTRUCTS

Structs are like simplified classes By default, all data and functions are public. A struct generally has

• no member functions• only data• no private stuff

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Lab 4


An ExampleAn Example

structemployType

{apstring fname;

apstring lname;

bool creditRisk;

int age;

double income;

}

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Lab 4


USEUSE

employType faculty;

faculty.fname = “sue”;

faculty.lname = “smith”;

faculty.creditRisk = false;

faculty.age = 21;

faculty.income = 38000.00;

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Lab 4


Why use structs???Why use structs???

structures data keeps information about 1 employee in one

place can manipulate employee (or a list of

employees) easily

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Lab 4


another example...another example...

struct studentnode

{

int id;

apstring first;

apstring last;

apvector<int> grades;

bool sports;

};

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Lab 4


int main()

{

apvector <studentnode> apcs(10);

int num;

int count=0;

apstring s;

ifstream instream ("f:\\trees\\studinfo.txt");

if (instream.fail())

cout <<"failed"<<endl;

else

{

cout<<"\tStudent ID#"<<"\t";

cout <<"Student Name"<<"\t"<<"GPA"<<endl;

out<<"\t==========="<<"\t============”

<<"\t==="<<endl;

111annsmith3.5222joejones3.24333amyjohnson2.86

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Lab 4


while (instream>>num )

{

apcs[count].id = num;

instream>>apcs[count].first;

instream>>apcs[count].last;

instream>>apcs[count].gpa;

apcs[count].sports = false;

cout<<setiosflags(ios::showpoint|ios::fixed);

cout<<setprecision(1);

cout<<"\t"<<setw(8)<<apcs[count].id;

cout<<"\t"<<apcs[count].first" ;cout "<<apcs[count].last<<"\

t"<<apcs[count].gpa<<endl;

cout<<endl;

count++;

}

} return(0);

}

111annsmith3.5222joejones3.24333amyjohnson2.86

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Lab 4


apvector of structsapvector of structs

student records employee records medical records sports statistics basketball teams...............

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Lab 4


CELTICS :::::

# fname lname position PPG

07 Kenny Anderson guard 12.1

08 Antoine Walker guard 18.7

34 Paul Pierce forward 16.5

40 Tony Battie center 10.0

05 Ron Mercer guard 17.0

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Lab 4


Celtics assignmentCeltics assignment

Read info from file celtics. fill array of structs. jersey # is not a field...it is the index of the

array element. Print team info in good format for the user.

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Lab 4


celticsceltics 0 1 2 3 4 5 6

Walter

McCarty

f

5.7

Ron

Mercer

g

17.0

Popeye

Jones

f

5.2

what does

this

look like

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Lab 4


structs with initializer listsstructs with initializer lists

Struct StudentType{StudentType(); //constructor member functionapstring last;apstring first;char initial;int class;GenderType gender;apvector<int> grades;}

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Lab 4


Using initializer listsUsing initializer lists

StudentType::StudentType()

:grades(10,-1)//grades initialized to 10 items each storing -1.

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Lab 4


Might want to look at struct3.cppMight want to look at struct3.cpp

initializer list for constructor of structstruct studentnode

{

int id;

apstring first;

apstring last;

double gpa;

bool sports;

studentnode(int num = 0, apstring f = "some first name", apstring l = "some last name", double g = 0.0, bool s = true):

id(num), first(f), last(l), gpa(g), sports(s)

{ }

};

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Lab 4


celticsceltics 0 1 2 3 4 5 6

Walter

McCarty

f

5.7

Ron

Mercer

g

17.0

Popeye

Jones

f

5.2

what

about

this?

none

none

x

0.0

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Lab 4


Celtics assignmentCeltics assignment Ask user to enter 5 jersey numbers. Inform user if team chosen if valid team (2 guards, 2

forwards, 1 center) User should be able to enter as many teams as he/she

wishes. invalid teams:

• guards<>2, center<>1,forwards<>2• player on team more than once• invalid jersey number entered

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Lab 4


After we have our apvector of celtics…

After we have our apvector of celtics…

What does a “team” look like???

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Lab 4


team ???team ???

Kenny

Anderson

g

12.1

???

apvector<playernode> ?

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Lab 4


team ???team ???

07

???

apvector<int> ?

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Lab 4


CELTICSCELTICS

Efficient check

vs

Inefficient check

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Lab 4


AquaFish revisitedAquaFish revisited

Keep a record of how many times each position in the fish tank was occupied by your fish.

• add to your aquafish private parts– apvector<int> myPositionCounts

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Lab 4


Print frequency distribution for a vector of aquafish

Print frequency distribution for a vector of aquafish

Our fish’s next experience with an apvector will be keeping a record of how many times each position in the fish tank was occupied by each of the fish in an apvector. Recall that our fish tank is represented by a number line of positions 0 to (tankSize – 1).

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Lab 4


Fish# Position Hits 0 1 2 3 4 5 6 7 8 9---------------------------------------------------------------------- 1 1 2 5 7 4 1 0 0 0 0 2 0 0 0 0 0 4 6 5 4 1 3 1 2 1 3 7 5 1 0 0 0 4 5 7 2 1 2 2 1 0 0 0 5 0 0 0 0 0 0 4 7 6 3 6 0 0 0 0 1 1 1 2 8 7 7 5 6 2 4 3 0 0 0 0 0 8 0 2 4 4 4 3 2 1 0 0

Tanksize = 10Steps in this simulation = 20Number of fish in this simulation = 8

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Lab 4


Modifications:Modifications: Change aquafish.h and aquafish.cpp so that there is

one default constructor requiring no parameters. Add a constant, TANKSIZE = 10 to aquafish.cpp Add a private data field to aquaFish.h

apvector<int> myPositionCounts . This vector will hold the frequency of position hits for one aquafish.

Add a void member function to print, in an appropriate format, the position counts of an aquafish : void PrintPositionCounts();

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Lab 4


ModificationsModifications

Add a void public member function, TankSize() that will return an Aquafish’s tanksize.

Set mydebugging to false Revise aquamain.cpp so that a sample run similar to

the one given will result. Notice that the constant TANKSIZE for this simulation was set to 10. There were 8 fish in the simulation (numbered 1-8). There were 20 steps in the simulation so that if you sum the elements of each fish’s positionCount vector, the result is 20.

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Lab 4


Lab 4

pages 20-38 in your labbook

MBCS pages 1-18

apcs lab 4

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