new with structs

[charmeda103]

I am writing a program that deals with structs.
i need help with structs this is my first time dealing with them. can you give me some examples that would be helpful.
my program is supposed to have to read data from two input files.
any inforamtion on stucts will be helpful.

thank
you

[Ganon11]

Structs are just a useful way to store related pieces of information together. For instance, let's consider the following very simple idea:

You are a teacher, and you want to store some basic information about your students - their name, their age, and their current grade (out of 100). You know you can code it like this:

string name;
int age;
double grade;

This would be fine if you had just 1 student, but you have closer to 30. OK, how about this approach?

string nameOfStud1, nameOfStud2, nameOfStud3; // ...and so on...
int ageOfStud1, ageOfStud2, ageOfStud3; // ...and so on...
double gradeOfStud1, gradeOfStud2, gradeOfStud3; // ...and so on...

Very messy - not at all what you wanted. So how to simplify this? One answer is to use arrays:

string names[30];
int ages[30];
double grades[30];

Not very satisfactory - yes, names[5], ages[5], and grades[5] all correspond to the 6th student, but what if you wanted to print out the student's names in alphabetical order, and had to sort that array to do so? Lots of messiness involved still.

The real answer is to use a simple struct:

struct Student {
   string name;
   int age;
   double grade;
};

Student myClass[30];

What is Student? It's just a fancy name for collecting three related pieces of data - a name, age, and grade - into the same structure. You can now (correctly) think of these pieces of data as a whole - a Student.

On the technical side, you must now refer to the data members in the following manner:

Student myStudent;
myStudent.name = "Ganon11";
myStudent.age = 130;
myStudent.grade = 100.0;

which is a trivial addition when compared to the massive confusion you've avoided.

[donbock]

Only one thing to add ... how to work with pointers to structures.

Student *pStudent;
pStudent->name = "Ganon11";
pStudent->age = 130;
pStudent->grade = 100.0;

Just apply the rules already given to handle structures that contain other structures or that contain pointers to other structures.

After you become a structural expert you should google the tem 'incomplete structure'.

Ganon11: Perhaps you feel that old today, but I'm sure you're usually quite spry. You're certainly confident you'll do well in this hypothetical class!

[Ganon11]

Only one thing to add ... how to work with pointers to structures.

Student *pStudent;
pStudent->name = "Ganon11";
pStudent->age = 130;
pStudent->grade = 100.0;

Make sure you allocate some memory for that struct, or you'll get a whole bunch of segmentation faults:

Student *pStudent = new Student;

Ganon11: Perhaps you feel that old today, but I'm sure you're usually quite spry. You're certainly confident you'll do well in this hypothetical class!

The rest of the students are young'uns - 20s and 30s all of em. Whippersnappers - back in my day, I had to walk uphill both ways in a snowstorm to access the Usenet.

[charmeda103]

can you use structs in void functions or do they have to be declared before main.
how would u use structs has a void function

[donbock]

can you use structs in void functions or do they have to be declared before main.
how would u use structs has a void function

By "void function" do you mean a function with no return value or a function with no arguments?

[charmeda103]

a void function like

void ReadStudentName (string,name,.. ......etc)

{
more code here
}
no return value necessary

[charmeda103]

I just started my program does it look like i am doing it right.

#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<fstream>



using namespace std;

struct schoolStats
{
	string schoolName;
	int numberWins;
	int numberLosses;
	int numberPointsTheTeamScored;
	int numberPointsScoreAganistTheTeam;
	int teamOverallWins;
	int teamOverallLosses;
	int numberPointsTheTeamScoredInAll;
	int numberPointsTheTeamScoredAganist;
}




int main()
{

	ifstream inFile1;
	inFile1.open("G:\\formerstats.txt");
	
	while(!inFile1.eof())
	{
	 






	}












	return 0;
}

[Ganon11]

Looks like you've got a great start.

[charmeda103]

ok now i am getting a bunch of errors help!

here are the messages:
error C2628: 'schoolStats' followed by 'void' is illegal (did you forget a ';'?)
syntax error : missing ',' before identifier 'string'
error C2065: 'schoolName' : undeclared identifier
error C2065: 'numberWins' : undeclared identifier
error C2065: 'numberPointsTh eTeamScored' : undeclared identifier
error C2065: 'numberPointsSc oreAganistTheTe am' : undeclared identifier
error C2065: 'teamOverallWin s' : undeclared identifier
error C2065: 'teamOverallLos ses' : undeclared identifier
error C2065: 'numberPointsTh eTeamScoredInAl l' : undeclared identifier
error C2065: 'numberPointsTh eTeamScoredAgan ist' : undeclared identifier
error C2146: syntax error : missing ',' before identifier 'string'
: error C2556: 'void SchoolStats(std ::ifstream &,std::strin g &,int &,int &,int &,int &,int &,int &,int &)' : overloaded function differs only by return type from 'schoolStats SchoolStats(std ::ifstream &,std::strin g &,int &,int &,int &,int &,int &,int &,int &)'
see declaration of 'SchoolStats'
error C2371: 'SchoolStats' : redefinition; different basic types
see declaration of 'SchoolStats'

#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<fstream>



using namespace std;

struct schoolStats
{
	string schoolName;
	int numberWins;
	int numberLosses;
	int numberPointsTheTeamScored;
	int numberPointsScoreAganistTheTeam;
	int teamOverallWins;
	int teamOverallLosses;
	int numberPointsTheTeamScoredInAll;
	int numberPointsTheTeamScoredAganist;
}

void SchoolStats(ifstream& inFile1 string&, int&, int&, int&, int&, int&, int&, int&);



int main()
{

	ifstream inFile1;
	inFile1.open("G:\\formerstats.txt");
	
	while(!inFile1.eof())
	{
	  SchoolStats(inFile1, schoolName, numberWins, numberPointsTheTeamScored, numberPointsScoreAganistTheTeam, teamOverallWins, teamOverallLosses, numberPointsTheTeamScoredInAll, numberPointsTheTeamScoredAganist);







	}












	return 0;
}
void SchoolStats(ifstream& inFile1 string& schoolName, int&numberWins, int&numberPointsTheTeamScored, int&numberPointsScoreAganistTheTeam, int&teamOverallWins, int&teamOverallLosses, int&numberPointsTheTeamScoredInAll, int&numberPointsTheTeamScoredAganist)
{
	 schoolStats stats[10];
		 stats[1].schoolName;
		 stats[1].numberWins;
		 stats[1].numberPointsTheTeamScored;
		 stats[1].numberPointsScoreAganistTheTeam;
		 stats[1].teamOverallWins;
		 stats[1].teamOverallLosses;
		 stats[1].numberPointsTheTeamScoredInAll;
		 stats[1].numberPointsTheTeamScoredAganist;

	
}

[boxfish]

You need a semicolon after the closing brace of your struct.
I hope this solves some of the errors.

[charmeda103]

please i am having a hard time with this program. can you help me fix these errors.

error C2146: syntax error : missing ',' before identifier 'string'
error C2065: 'schoolName' : undeclared identifier
error C2065: 'numberWins' : undeclared identifier
error C2065: 'numberPointsTh eTeamScored' : undeclared identifier
error C2065: 'numberPointsSc oreAganistTheTe am' : undeclared identifier
error C2065: 'teamOverallWin s' : undeclared identifier
error C2065: 'teamOverallLos ses' : undeclared identifier
error C2065: 'numberPointsTh eTeamScoredInAl l' : undeclared identifier
error C2065: 'numberPointsTh eTeamScoredAgan ist' : undeclared identifier

#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<fstream>



using namespace std;

struct schoolStats
{
	string schoolName;
	int numberWins;
	int numberLosses;
	int numberPointsTheTeamScored;
	int numberPointsScoreAganistTheTeam;
	int teamOverallWins;
	int teamOverallLosses;
	int numberPointsTheTeamScoredInAll;
	int numberPointsTheTeamScoredAganist;
};

void SchoolStats(ifstream& inFile1 string&, int&, int&, int&, int&, int&, int&, int&);



int main()
{

	ifstream inFile1;
	inFile1.open("G:\\formerstats.txt");
	
	while(!inFile1.eof())
	{
	  SchoolStats(inFile1, schoolName, numberWins, numberPointsTheTeamScored, numberPointsScoreAganistTheTeam, teamOverallWins, teamOverallLosses, numberPointsTheTeamScoredInAll, numberPointsTheTeamScoredAganist);

	}


	return 0;
}
void SchoolStats(ifstream& inFile1, string& schoolName, int&numberWins, int&numberPointsTheTeamScored, int&numberPointsScoreAganistTheTeam, int&teamOverallWins, int&teamOverallLosses, int&numberPointsTheTeamScoredInAll, int&numberPointsTheTeamScoredAganist)
{
	 schoolStats stats[10];
	 
	cout<<stats[1].schoolName;
	cout<<stats[1].numberWins;
	cout<<stats[1].numberPointsTheTeamScored;
	cout<<stats[1].numberPointsScoreAganistTheTeam;
	cout<<stats[1].teamOverallWins;
	cout<<stats[1].teamOverallLosses;
	cout<< stats[1].numberPointsTheTeamScoredInAll;
    cout<<stats[1].numberPointsTheTeamScoredAganist;

	
}

[boxfish]

The first error means what it says; you're missing a comma between the first two parameters in the declaration of your SchoolStats function. As for the other errors, they're problems with the arguments you're passing to SchoolStats. I'm not sure what you were trying to do there. What is the SchoolStats function supposed to do?

[charmeda103]

i changed the program a bit its supposed to read information from a file.



here is the error message. i cant figure out how to fix it.



error C2065: 'schoolName' : undeclared identifier
error C2065: 'basketball' : undeclared identifier
error C2228: left of '.schoolName' must have class/struct/union

How do i declare this

#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<fstream>



using namespace std;

void SchoolStats(ifstream& inFile1, string&);

struct basketballStats
{
	string schoolName;
	int numberWins;
	int numberLosses;
	int numberPointsTheTeamScored;
	int numberPointsScoreAganistTheTeam;
	int teamOverallWins;
	int teamOverallLosses;
	int numberPointsTheTeamScoredInAll;
	int numberPointsTheTeamScoredAganist;
};

 


int main()
{

	ifstream inFile1;
	inFile1.open("G:\\formerstats.txt");
	
	while(!inFile1.eof())
	{

		  SchoolStats( inFile1,schoolName);
		  cout<<basketballStats.schoolName;


	}

	return 0;
}
void SchoolStats(ifstream& inFile1, string& schoolName)
{
	 
	 basketballStats mystats[10];
	
		
	cout<<basketball[1].schoolName="BW";
	

	
}

[Ganon11]

void SchoolStats(ifstream& inFile1, string& schoolName)
{
	 
	 basketballStats mystats[10];
	
		
	cout<<basketball[1].schoolName="BW";
	

	
}

Let's look at what you've done here. You've declared an array of basketballStats struct called mystats. Then you are trying to output from basketball[1]. What is basketball? You never declared it! You're not using the array you just created, like you should be. Plus, you're trying to assign to a variable in the same statement as your output.

You should be manipulating mystats[0], mystats[1], etc...up to mystats[9].