Question about the getline function

jmg0880 · 11-02-2009, 10:29 PM

I am trying to use the getline function in order to have a user input a students name. The code is as followed.

The Structure:

Code:

struct student	// the student structure meant to hold all student data 
				// in a linked list fashion
{
	char	studentNames[maxStudents][lnName];	//	student names
	int sectionNum;								// section the student is in
	float project[11];							// student's projects
	float test[3];								// students's tests
	float quiz[5];								 // students's quizzes

	student *nxt;								 // pointer to next student
}; // end struct student

The Function:

Code:

void	getStudentNames (char pgmID[],		char title[], char subTitle[], 
						 char gradebookName[]	)
{
	//	Declare local vbls for holding data that is inputted by the user.
	int numStudents;
	student *temp;

	//	Display title and sub-title lines.
	system ("cls");
	cout	<<	pgmID	<<	setw ( 40 + strlen(title) / 2 - strlen(pgmID)) << title	<<	endl;
	cout	<<	setw ( 40 + strlen(subTitle) / 2) << subTitle << "\n\n\n";

	//	If warranted, open the file for output.
	ofstream	gradeBookFile;
	gradeBookFile.open (gradebookName, ios::out);

	//	Input data for this item from the user and output it to the database.	
		cout << "\t\tPlease enter the number of students: ";
		cin >> numStudents;
		cin.ignore();

		//	Input data for this item from the user and output it to the database.
		for ( int count = 0; count < numStudents; count++ )
		{
			
			cout	<<	"\n\t\tPlease enter student name (L F MI): ";
			temp = new student;
			cin.getline ( temp[count] ->studentNames, lnName );
			
			gradeBookFile << temp->studentNames[count] << endl;
		} // end for ( int count = 0 ....

	
	//	Close the file, return to sender.
	gradeBookFile.close();
}	//	end getStudentNames (...

The error is at the getline function.

I don't know how to properly do this

HELP PLEASE!

Dino · 11-02-2009, 10:42 PM

And the error is.... ????

By the way, your struct should look like this:

Code:

struct student	// the student structure meant to hold all student data 
				// in a linked list fashion
{
	char	studentNames[maxStudents][lnName];	//	student names
	int sectionNum;								// section the student is in
	float project[11];							// student's projects
	float test[3];								// students's tests
	float quiz[5];								 // students's quizzes

	struct student *nxt;								 // pointer to next student
}; // end struct student

jmg0880 · 11-02-2009, 10:47 PM

The error is :

error C2819: type 'student' does not have an overloaded member 'operator ->'

and also

error C2232: '->student::studentNames' : left operand has 'struct' type, use '.'

jmg0880 · 11-03-2009, 08:47 AM

I really need help!

Dino · 11-03-2009, 08:51 AM

I am home sick today - so this is the best I care to offer right now.

When working with structs, when you have one statically allocated, you use dot notation to access its members.

When working with pointers to structs, you use arrow notation.

jmg0880 · 11-03-2009, 09:10 AM

Quote:

Originally Posted by Dino

I am home sick today - so this is the best I care to offer right now.

When working with structs, when you have one statically allocation, you use dot notation to access its members.

When working with pointers to structs, you use arrow notation.

Thanks man, I will try that tonight and let you know how it works out

hk_mp5kpdw · 11-03-2009, 12:35 PM

Quote:

Originally Posted by Dino

And the error is.... ????

By the way, your struct should look like this:

Code:

struct student	// the student structure meant to hold all student data 
				// in a linked list fashion
{
	char	studentNames[maxStudents][lnName];	//	student names
	int sectionNum;								// section the student is in
	float project[11];							// student's projects
	float test[3];								// students's tests
	float quiz[5];								 // students's quizzes

	struct student *nxt;								 // pointer to next student
}; // end struct student

Huh, should be fine in C++ without the struct keyword in front of student. In C yes that would be a problem.

Code:

for ( int count = 0; count < numStudents; count++ )
{
    cout << "\n\t\tPlease enter student name (L F MI): ";
    temp = new student;
    cin.getline ( temp[count] ->studentNames, lnName );

You aren't creating arrays of students here so why are you attempting to access them like temp is an array? You are creating single instances each time through the loop. You also aren't doing anything to link the nodes together into a linked list.

Any errors in the above I attribute to the Vicodin I'm currently taking... good stuff.

jmg0880 · 11-03-2009, 01:16 PM

Quote:

Originally Posted by hk_mp5kpdw

Huh, should be fine in C++ without the struct keyword in front of student. In C yes that would be a problem.

Code:

for ( int count = 0; count < numStudents; count++ )
{
    cout << "\n\t\tPlease enter student name (L F MI): ";
    temp = new student;
    cin.getline ( temp[count] ->studentNames, lnName );

You aren't creating arrays of students here so why are you attempting to access them like temp is an array? You are creating single instances each time through the loop. You also aren't doing anything to link the nodes together into a linked list.

Any errors in the above I attribute to the Vicodin I'm currently taking... good stuff.

I just want to be able to type in a full name and grabbing a char that is declared in the structure like, for example,

Billy Bob M

Elysia · 11-03-2009, 01:19 PM

Then it would be
temp->studentNames[count]
The index comes after the actual variable whose elements you want to access.
Disclaimer: I have not checked this for rightness. I am simply explaining how it should be done.

11-02-2009, 10:42 PM	#2
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 2,175	And the error is.... ???? By the way, your struct should look like this: Code: struct student // the student structure meant to hold all student data // in a linked list fashion { char studentNames[maxStudents][lnName]; // student names int sectionNum; // section the student is in float project[11]; // student's projects float test[3]; // students's tests float quiz[5]; // students's quizzes struct student *nxt; // pointer to next student }; // end struct student __________________ Mac and Windows cross platform programmer. Ruby lover. Quote of the Day 8/19: brewbuck: I do not recommend the above. In fact, it's so disgusting that I've blanked it out because you'd probably take it and run with it.
Dino is offline

11-02-2009, 10:47 PM	#3
jmg0880 Registered User Join Date: Nov 2009 Posts: 5	The error is : error C2819: type 'student' does not have an overloaded member 'operator ->' and also error C2232: '->student::studentNames' : left operand has 'struct' type, use '.'
jmg0880 is offline

11-03-2009, 08:47 AM	#4
jmg0880 Registered User Join Date: Nov 2009 Posts: 5	I really need help!
jmg0880 is offline

11-03-2009, 08:51 AM	#5
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 2,175	I am home sick today - so this is the best I care to offer right now. When working with structs, when you have one statically allocated, you use dot notation to access its members. When working with pointers to structs, you use arrow notation. __________________ Mac and Windows cross platform programmer. Ruby lover. Quote of the Day 8/19: brewbuck: I do not recommend the above. In fact, it's so disgusting that I've blanked it out because you'd probably take it and run with it. Last edited by Dino; 11-03-2009 at 09:51 AM. Reason: typo
Dino is offline

11-03-2009, 01:19 PM	#9
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,550	Then it would be temp->studentNames[count] The index comes after the actual variable whose elements you want to access. Disclaimer: I have not checked this for rightness. I am simply explaining how it should be done. __________________ WARNING: Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
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