string array in c++

[emeric]

can somebody help me:(

i don't know what's wrong with my program:
this is my header file:
// StudentInformation.h file

#include <string> // uses string class
using std::string;

// StudentInformation class definition
class StudentInformation
{
public:
const static int students = 30; // constant number of student in the class
studentInformation ( string, string, double ); // constructor that initialize the firstname, lastname and Finalscore.
void setFirstName ( string ); // function that set the first name
string getFirstName (); // function that get the first name
void setLastName ( string ); // function that set the last name
string getLastName (); // function that get the last name
void setFinalScore ( double ); // function that set the final score
double getFinalScore (); // function that get the final score
void print (); // function that print the first name, last name and the final score
void printGrades (); // function that print all the students first name, last name and the final grade
double lowestScore (); // function that determine the lowest score
double highestScore (); // function that determine the highest score
double avgScore (); // function that determine the average score
void add ( string, string, double );
private:
string firstName; // firstname for this student information class
string lastName; // lastname for this student information class
double finalScore; // final score for this student information class
string fName[ students ]; // array of students' first name for the student information class
string lName[ students ]; // array of students' last name for the student information class
double fScore[ students ]; // array of student final score for the student information class
}; // end class student information



then this is my .cpp file:
// StudentInformation II.cpp
// Define class studentInformation that contains firstName, lastName, finalScore data
// and member functions to set and get its value.
#include <iostream> // allows program to perform input and output data
// to the screen
using namespace std;

#include <string> // program uses C++ standard string class
using namespace std;

#include <iomanip>
using namespace std;

#include "StudentInformation II.h"

// StudentInformation constructor initializes header, firstname and
// lastname with string supplied as argument and the array finalScore.
StudentInformation::StudentInformation( string f, string l, double s )
{
setFirstName( f ); // initialize firstName
setLastName( l ); // initialize lastName
setFinalScore(s);// initialize finalScore
} // end of constructor

void add( string f, string l, double s )
{
static double max = 0; // initialize first time add is called

// if max is less than students, copy firstName, lastName and finalScore into their respective arrays.
if ( max < students )
{
string fName[ max ] = firstName; // store firstName in array firstName
string lName[ max ] = lastName; // store lastName in array lastName
string fScore[ max ] = finalScore; // store finalScore in array finalScore
max++; // increment max by 1
}

} // end of constructor

// function that gets the first name
string StudentInformation::getFirstName()
{
return firstName; // return object's firstName
} // end function getFirstName

// function that sets the first name
void StudentInformation::setFirstName( string f )
{
firstName = f; // store the first name in the object
} // end function setFirstName

// function that gets the last name
string StudentInformation::getLastName()
{
return lastName; // return object's lastName
} // end function getLastName

// function that sets the last name
void StudentInformation::setLastName( string l )
{
lastName = l; // store the last name in the object
} // end function setLastName

// function that gets the finalScore
double StudentInformation::getFinalScore()
{
return finalScore; // return object's finalScore
} // end function getFinalScore

//function that sets the finalScore
void StudentInformation::setFinalScore( double s )
{
finalScore = s; // store the final score in the object
} // end function setFinalScore

// find minimum score
double StudentInformation::lowestScore()
{
double lowScore = 100; // assume lowest grade is 100

// loop through finalScore array
for ( int student = 0; student < max; student++ )
{
// if current score lower than lowScore, assign it to lowScore
if ( fScore[ student ] < lowScore )
lowScore = fScore[ student ]; // new lowest score
} // end the for loop

return lowScore; // return lowest score
} // end function lowestScore

// find maximum score
double StudentInformation::highestScore()
{
double highScore = 0; // assume highest score is 0


// loop through finalScore array
for ( int student = 0; student < max; student++ )
{
// if current score higher than highScore, assign it to highGrade
if ( fScore[ student ] > highScore )
highScore = fScore[ student ];
} // end for

return highScore; // return highest grade
} // end function highestScore

// find average score
double StudentInformation::avgScore()
{
double total = 0; // initialize total

// sum scores in array
for ( int student = 0; student < max; student++ )
total += fScore[ student ];

// return average of scores
return total / max;
} // end function average score

// function that print first name, last name and the final grade of all the students
void StudentInformation::printGrades()
{
// output each student grade
for ( int student = 0; student < max; student++ )
{
if ( fScore[ student ] >= 90 ) // if final score is more than 90, print Final Grade is A
cout<< "\n" << fName[ student ] << setw(10) << lName[ student ] << setw(10) << "Final Grade is A";
else if ( fScore[ student ] >= 80 ) // if final score is more than 80, print Final Grade is B
cout<< "\n" << fName[ student ] << setw(10) << lName[ student ] << setw(10) << "Final Grade is B";
else if ( fScore[ student ] >= 70 ) // if final score is more than 70, print Final Grade is C
cout<< "\n" << fName[ student ] << setw(10) << lName[ student ] << setw(10) << "Final Grade is C";
else if ( fScore[ student ] < 70 ) // if final score is less than 70, print Final Grade is F
cout<< "\n" << fName[ student ] << setw(10) << lName[ student ] << setw(10) << "Final Grade is F";
} // end for loop
} // end function that print the grades of all the students

// function that print first name, last name and finalScore
void StudentInformation::print()
{
cout<< "\n\nFirst Name" << setw(10) << "Last Name" << setw(10) << "Final Score\n\n";

// output each student's score
for ( int student = 0; student < max; student++ )
cout<< fName[ student ] << setw(10) << lName[ student ] << setw(10) << fScore[ student ] <<"\n";
} // end function print


now, this is my main() file:

// function main of StudentInformation II.cpp
#include <iostream>
using namespace std;

#include "StudentInformation II.h" // Include definition of class StudentInformation II

// function main begins program execution
int main()
{
// create one studentInformation object
StudentInformation myStudentInformation1( "Emeric", "Bechi", 95);
myStudentInformation1.print();
StudentInformation myStudentInformation2( "Isaac", "Newton", 100 );
myStudentInformation2.print();
system ("pause");
} // end main


now, this is the errors that i get:
5 C:\Dev-Cpp\StudentInformationIV.cpp In file included from C:\Dev-Cpp\StudentInformationIV.cpp

11 C:\Dev-Cpp\StudentInformation II.h ISO C++ forbids declaration of `studentInformation' with no type

C:\Dev-Cpp\StudentInformationIV.cpp In function `int main()':

11 C:\Dev-Cpp\StudentInformationIV.cpp no matching function for call to `StudentInformation::StudentInformation(const char[7], const char[6], int)'

[Code_Nerd]

I just tried to run it in VS7 and you have many many errors.

For starters your default constructor is missing a capital S in studentInformation!

You are trying to use 'max' in numerous functions that don't know it exists..

[emeric]

i just realize that. and i fixed it by putting the max value in the header file as a public data. however it still gives me that same error which is:
11 F:\Dev-Cpp\StudentInformation.h ISO C++ forbids declaration of `studentInformation' with no type .

and i have no idea why it doesn't recognize my constructor.

[Code_Nerd]

i just realize that. and i fixed it by putting the max value in the header file as a public data. however it still gives me that same error which is:
11 F:\Dev-Cpp\StudentInformation.h ISO C++ forbids declaration of `studentInformation' with no type .

and i have no idea why it doesn't recognize my constructor.

studentInformation is not the same as StudentInformation

[emeric]

i did that too. i meant, i fixed both of my mistakes, but i still get the same error message.

[Greggle]

By which you mean: you get the same error at the same line of code, line 11 in this case?

[emeric]

now, this is the error that i get:
26 F:\Dev-Cpp\StudentInformation.h ISO C++ forbids in-class initialization of non-const static member `max'

i don't know why i can't initialize 'max' etheir in public or in private.

[Danny]

You can't initialize data members inside the class. They must be initialized in the constructor. The only except is const static integral data.

[emeric]

thank you for your help Everybody. however, my concern is that, i'm trying to use the 'max' value throughout the whole program. in that case, where should i declare it ? i declared it in the constructor but it gives me bunch of error message in the functions where i used the 'max' value.:confused:

[jonnin]

in the cpp file do this:

static const double classname::value = 3.1415;


in the class (header file), make a member:

double value;

also, beware 'max' as it is used as a macro in many systems.


alternately, just put
double value; in your class header file and in the ctor put
value = 3.1415; to assign it (just remember that its a const and should never be on lhs).

[emeric]

thank you for your response. my problem is that i want to be able to increment the 'max' value. so in that case, i can't declare it as a const, can I?
if not, how can i declare it and where in my cpp file and my header file?

[jonnin]

put in the class as a member, your call on public or private.

-If it is shared across all your class instances, make it static as I described but without the const.

-Initialize it in the constructor, or, if static, in the cpp file.