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Jan 12th, 2009

Struct and Char not handling space properly

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I'm writing a class planner, where the user is given the opportunity to enter certain information about their classes and have it printed back to them upon request.

The problem I'm having is that whenever I enter any text into the input with a space in it, it returns me to menu().
I also tried using string in my structured array, but then it simply skipped the entire input for that variable.

I'm using a struct in my header file to allow simple input into the array:

C++ Syntax (Toggle Plain Text)
struct Classes
{
	char ClassName[30];
	int	ClassNumber;
	char DaysMet[20];
	int StartTime;
	int	EndTime;
	char Teacher[20];
	int Students;
};
struct Classes
{
	char ClassName[30];
	int	ClassNumber;
	char DaysMet[20];
	int StartTime;
	int	EndTime;
	char Teacher[20];
	int Students;
};

and here is the input form:

c++ Syntax (Toggle Plain Text)
int Input()
{	
	system("cls");
	if (currentindex > IndexNum)
		cout << "Index is full" << endl;
	else while (currentindex < IndexNum)
	{	cout << "Class Name: ";
		cin >> Course[currentindex].ClassName;
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;
		cout << "Days Met: ";
		cin >> Course[currentindex].DaysMet;
		cout << "Start Time: ";
		cin >> Course[currentindex].StartTime;
		cout << "End Time: ";
		cin >> Course[currentindex].EndTime;
		cout << "Teacher: ";
		cin >> Course[currentindex].Teacher;
		cout << "Students: ";
		cin >> Course[currentindex].Students;	
 
		currentindex++;
	}
 
	Menu();
	return 0;
}
int Input()
{	
	system("cls");
	if (currentindex > IndexNum)
		cout << "Index is full" << endl;
	else while (currentindex < IndexNum)
	{	cout << "Class Name: ";
		cin >> Course[currentindex].ClassName;
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;
		cout << "Days Met: ";
		cin >> Course[currentindex].DaysMet;
		cout << "Start Time: ";
		cin >> Course[currentindex].StartTime;
		cout << "End Time: ";
		cin >> Course[currentindex].EndTime;
		cout << "Teacher: ";
		cin >> Course[currentindex].Teacher;
		cout << "Students: ";
		cin >> Course[currentindex].Students;	
		
		currentindex++;
	}
	
	Menu();
	return 0;
}

Another way I attempted to get the program to accept input into my char 'ClassName'

c++ Syntax (Toggle Plain Text)
cin.getline(Course[currentindex].ClassName, 30)
cin.getline(Course[currentindex].ClassName, 30)

So, basically anyone who uses this program cannot enter data into the program when the variable has more than one word, for example:

Class Name: "Civics and Economics"
or
Teacher: "Mr. Mathus"

would send the user back to the main menu!

I'm totally clueless as to how to resolve this problem, thanks in advance!

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lameassthemity

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Jan 12th, 2009

Re: Struct and Char not handling space properly

Use std::string with getline

C++ Syntax (Toggle Plain Text)
#include <string>
...
std::string myString;
getline(std::cin, myString);
#include <string>
...
std::string myString;
getline(std::cin, myString);

Hope that helps

Chris

Last edited by Freaky_Chris; Jan 12th, 2009 at 6:21 pm.

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Jan 13th, 2009

Re: Struct and Char not handling space properly

Well, I'm not getting compiler errors now that I'm using the strings properly, but I'm still having trouble accepting input into the strings.

I've tried using a couple methods of input:
(not all at the same time of course)

c++ Syntax (Toggle Plain Text)
		getline(std::cin, Course[currentindex].ClassName);  // when the program runs, it skips this line entirely, jumping to 
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;
		getline(std::cin, Course[currentindex].ClassName);  // when the program runs, it skips this line entirely, jumping to 
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;

Producing a result in the application looking like this:

Class Name: Class Number:

c++ Syntax (Toggle Plain Text)
		cin >> Course[currentindex].ClassNumber;
		cin.getline(Course[currentindex].ClassName, []);  // Doesn't work with strings, obviously.
		cin >> Course[currentindex].ClassNumber;
		cin.getline(Course[currentindex].ClassName, []);  // Doesn't work with strings, obviously.

c++ Syntax (Toggle Plain Text)
		cin >> Course[currentindex].ClassName;  // works for single word answers, but goes to menu() if the input contains a space
		cin >> Course[currentindex].ClassName;  // works for single word answers, but goes to menu() if the input contains a space

lameassthemity

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Jan 13th, 2009

Re: Struct and Char not handling space properly

do you fdefine your ClassName as a string or a char array?

Freaky_Chris

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Jan 13th, 2009

Re: Struct and Char not handling space properly

My header file after your recommendation:

c++ Syntax (Toggle Plain Text)
#include <string>
using std::string;
 
struct Classes
{
	string ClassName;
	int	ClassNumber;
	string DaysMet;
	int StartTime;
	int	EndTime;
	string Teacher;
	int Students;
 
};
#include <string>
using std::string;

struct Classes
{
	string ClassName;
	int	ClassNumber;
	string DaysMet;
	int StartTime;
	int	EndTime;
	string Teacher;
	int Students;

};

lameassthemity

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Jan 13th, 2009

Re: Struct and Char not handling space properly

Ok,this is the else part of your loop

C++ Syntax (Toggle Plain Text)
<div> <div class="quote"> <div class="quote_header">   Quote ...   </div> <blockquote class="quote_body"> cout << "Class Name: ";
cin >> Course[currentindex].ClassName;
cout << "Class Number: ";		
cin >> Course[currentindex].ClassNumber; </blockquote> </div> </div>
<div> <div class="quote"> <div class="quote_header">   Quote ...   </div> <blockquote class="quote_body"> cout << "Class Name: ";
cin >> Course[currentindex].ClassName;
cout << "Class Number: ";		
cin >> Course[currentindex].ClassNumber; </blockquote> </div> </div>

When you use a cin statement ,the cin stops reading the buffer after it encounters a white space or a newline.So when you read something like this:
"Civics and Economics"
there are spaces and you have got only "Civics" in your

C++ Syntax (Toggle Plain Text)
Course[currentindex].ClassName
Course[currentindex].ClassName

and the rest part remains in your input stream(inclusive of the newline character).
All these things can be handled by using getline function.
The syntax of using getline with strings is

C++ Syntax (Toggle Plain Text)

getline(input_stream,name_of_string)

When you use getline it handlees the the newline ('\n') character (actually converts and appends '\t' to the end of the string) and you don't have to worry about the subsequent lines.
But getline stops reading when it encounters '\n'.So if this is stuck in your input stream getline fails.

I would suggest that you club all your "string input" statements together and all "numerical data " statements together.

But if you don't have a choice then you can discard the '\n' by

C++ Syntax (Toggle Plain Text)
cout << "Class Name: ";
cin >> Course[currentindex].ClassName;
char junk;
cin.get(junk);//gets the '\n' character
//even cin.ignore() works
cout << "Class Number: ";		
cin >> Course[currentindex].ClassNumber;
cout << "Class Name: ";
cin >> Course[currentindex].ClassName;
char junk;
cin.get(junk);//gets the '\n' character
//even cin.ignore() works
cout << "Class Number: ";		
cin >> Course[currentindex].ClassNumber;

Last edited by zalezog; Jan 13th, 2009 at 3:03 pm.

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Jan 13th, 2009

Re: Struct and Char not handling space properly

Click to Expand / Collapse Quote originally posted by zalezog ...

c++ Syntax (Toggle Plain Text)
//even cin.ignore() works
//even cin.ignore() works

Perfect! Thanks!

c++ Syntax (Toggle Plain Text)
 
{	
	system("cls");
	if (currentindex > IndexNum)
		cout << "Index is full" << endl;
	else while (currentindex < IndexNum)
	{	
		cout << "Class Name: ";		
		cin.ignore(); // <----
		getline(cin, Course[currentindex].ClassName);
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;
		cout << "Days Met: ";
		cin.ignore(); // <----
		getline(cin, Course[currentindex].DaysMet);
		cout << "Start Time: ";
		cin >> Course[currentindex].StartTime;
		cout << "End Time: ";
		cin >> Course[currentindex].EndTime;
		cout << "Teacher: ";
		cin.ignore(); // <----
		getline(cin, Course[currentindex].Teacher);
		cout << "Students: ";
		cin >> Course[currentindex].Students;	
 
		currentindex++;
	}
 
	Menu();
	return 0;
}
{	
	system("cls");
	if (currentindex > IndexNum)
		cout << "Index is full" << endl;
	else while (currentindex < IndexNum)
	{	
		cout << "Class Name: ";		
		cin.ignore(); // <----
		getline(cin, Course[currentindex].ClassName);
		cout << "Class Number: ";
		cin >> Course[currentindex].ClassNumber;
		cout << "Days Met: ";
		cin.ignore(); // <----
		getline(cin, Course[currentindex].DaysMet);
		cout << "Start Time: ";
		cin >> Course[currentindex].StartTime;
		cout << "End Time: ";
		cin >> Course[currentindex].EndTime;
		cout << "Teacher: ";
		cin.ignore(); // <----
		getline(cin, Course[currentindex].Teacher);
		cout << "Students: ";
		cin >> Course[currentindex].Students;	
		
		currentindex++;
	}
	
	Menu();
	return 0;
}

lameassthemity

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Jan 13th, 2009

Re: Struct and Char not handling space properly

I advise you use getline() for ALL data types and use string streams to convert them to int etc rather than cin.ignore()!

Chris

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Jan 13th, 2009

Re: Struct and Char not handling space properly

Click to Expand / Collapse Quote originally posted by Freaky_Chris ...

I advise you use getline() for ALL data types and use string streams to convert them to int etc rather than cin.ignore()!
Chris

What do you mean use string steams to convert them?

lameassthemity

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Jan 13th, 2009

Re: Struct and Char not handling space properly

Refer http://www.daniweb.com/tutorials/tutorial71858.html

zalezog

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