Programming Forums > Application Development > C++

nnxion · Apr 11th, 2006, 2:40 AM

OMGBBQ111elevenHashbang David, your function and variable names are catAssTrophicly BadStard.

codylee270 · Apr 11th, 2006, 1:24 PM

So you made the class and used it as a structure, not worrying about defining class methods and made the variables public. Does making the class variables public allow you to do whatever you want with them?

DaWei · Apr 11th, 2006, 1:48 PM

The only difference between a class and a structure in C++ is that the structure is by default public, and the class is by default private. I would have used a structure, but I decided AFTER making the class to make it public and avoid writing the getter/setter methods. It isn't a good idea, generally, but it was a short example. You'll note how simple it is to make a class -- it almost looks like a function with no code and local variables. Note that, unlike a function, it has to be followed by a semicolon. The class/structure does NOT generate code, typically. It is a pattern for an object that is later created by instantiating it. "bastardRecord theData;" makes one. Another one is made each time I copy theData into a vector. Objects scare a lot of people because self-appointed high-priest/gurus like to gold-plate their mantles and make acolytes kiss their asses. A lawnmower is an object. Mowing the lawn is procedural. Big deal. You might want to read the little blurb in my signature, "OOD, My View". Properly used, it's a helluva tool.

Ruben, when I write code for myself, I can be as informal as I like

.

codylee270 · Apr 11th, 2006, 2:18 PM

I have read both your view and the thing on pointers, and not only is the pointer page funny, but it's probably the clearest and most illustrative explanation that i've ever seen... And I know that i've asked you before, wise ol' man, but what have you done career-wise to gain such experience with your computer languages?

codylee270 · Apr 11th, 2006, 3:05 PM

And while you are still reading this thread, I've done the reformatting so that the file only saves as raw data with a single space between data. I'm trying to write the program that will read in the file and let you change the data, so as i'm reading it in from the file line by line, i'm splitting it up on the spaces, and funneling them into their respective arrays: BUT, i've got an error on one of them:

Please take a look:

(Toggle Plain Text)

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
#include <iomanip>
#include <vector>
#include <cstdlib>
using namespace std;


int main()
{
	int i=0,j=0,id[10];
	vector<int> years;
	char sex[10];
	float wage[10];
	int yearsworked;
    ifstream infile;
    ofstream outfile;
    string disp1, disp2, filename;
    string line;

    cout << "Please input the name of the file you wish to open: " ;
    getline(cin, filename);
    
    infile.open(filename.c_str());
    if(infile.fail())
    {
                      cout <<"\nThe file was not successfully opened." << endl;
                      exit(1);
    }
    

    //Parsing
    while(getline(infile,line))
    {
         int s1 = line.find(" ");
         int s2 = line.find(" ");
         int s3 = line.find(" ");
         
         id[i] = atoi(line.substr(0, s1).c_str());
         sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str();
         wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str());
         years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str());
         
         i++;
    }
    
    infile.close();
         
  
	system("PAUSE");
	return 0;
}

There error is: invalid conversion from `const char*' to `char'

corresponds to :

(Toggle Plain Text)

 
sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str();

What's the fix for this? After that, I'm going to let the users change certain data, but I gotta have the data first!!!

DaWei · Apr 11th, 2006, 3:17 PM

You can't assign a c-string to a single character, which is what sex [index] is. I cautioned you earlier to forget treating gender as a single character, because it limits your options. I don't understand why you're regressing to (forgive me) trash code.

codylee270 · Apr 11th, 2006, 3:21 PM

no, please forgive me..lol.. Through the lengthy posts i forgot to change it to a string, which I did. It now compiles but crashes after completion......................

codylee270 · Apr 11th, 2006, 5:15 PM

I've continued building onto the program, but I would like someone to explain to me why it crashes before I post newer, longer code to make the issue more confusing. Thanks!

DaWei · Apr 11th, 2006, 5:50 PM

Post your new code. You may be overflowing an array, which is why you should be using vectors. You have no idea what the size of the file may be (in a practical world), so you're always going to have problems allocating. Failure to put the items into a structure that aggregates them destroys the interrelationship that they naturally possess. You don't need to search the line for the separator; that's what the various input methods are for. The separator is probably better if it's a non-space (like a comma). You might introduce a name field and want "Joe Bob" to be one item.

codylee270 · Apr 11th, 2006, 6:02 PM

Alrighty, I know it's long, but i've been building on it. I've got a lot more on the end of it for saving the file, but i'll take it off just for the sake of length (even though its drawn out already. I've got an another few errors, and I'm thinking they all stem from the initial error. I'll elaborate below:

(Toggle Plain Text)

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
#include <iomanip>
#include <vector>
#include <cstdlib>
#include <algorithm>
using namespace std;


int main()
{
	int i=0, j=0, holder, offset;
	vector<int> years;
	vector<int> id;
	string sex[10];
	float wage[10];
	int yearsworked, selection;
	
    ifstream infile;
    ofstream outfile;
    
    string disp1, disp2, filename, line;
    
    char selection2, selection3, selection4;
    
    // -----------------  Begin program body ----------------------------------

    cout << "Please input the name of the file you wish to open: " ;
    getline(cin, filename);
    bool found;
    
    infile.open(filename.c_str());
    if(infile.fail())
    {
                      cout <<"\nThe file was not successfully opened." << endl;
                      exit(1);
    }
    
    //Parsing
    while(getline(infile,line))
    {
         int s1 = line.find(" ");
         int s2 = line.find(" ");
         int s3 = line.find(" ");
         
         id.push_back(atoi(line.substr(0, s1).c_str()));
         sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str();
         wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str());
         years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str());
         
         i++;
    }
    
    infile.close();
    
    cout << "The file contained the following:" << endl << endl;
    
	cout <<"Employee ID       " << "Employee Sex         " << "Numeric Wage        "  
         << "Years with Company" << endl;
	cout << "-----------       " << "------------         " 
         << "------------        " << "------------------" << endl;

	for(j=0; j<2; j++)
	{
		cout << setw(11) << right << id[j] << "       "	<< setw(12) << sex[j] << "         " << "$  " 
             << setw(9) << fixed << setprecision(2) << right << wage[j] << "        " 
             << setw(18) <<	right << years[j] << endl;
	}
	vector<int> idcopy(id);
	sort(idcopy.begin(), idcopy.end());
    
    more: //for goto
         
    cout << "\nTo change the hourly wage or years with the company ";
    cout << "for an employee, please enter the ID # from above: ";
	cin >> selection;
	cin.ignore();
	
	
	found = binary_search(idcopy.begin(),idcopy.end(), selection);
	

	while(!found)
    {
                 cout << "\nThe Employee ID No: " << selection <<" was not found." 
                      << "\nPlease select another from the list provided:" ;
                 cin >> selection;
                 cin.ignore();
                 found = binary_search(idcopy.begin(),idcopy.end(), selection);
                      
    }
	
     cout <<"\nEmployee ID       " << "Employee Sex         " << "Numeric Wage        "  
          << "Years with Company" << endl;
     cout << "-----------       " << "------------         " 
          << "------------        " << "------------------" << endl;
                 
     offset = find(id.begin(),id.end(), selection);

	system("PAUSE");
	return 0;
}

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
#include <iomanip>
#include <vector>
#include <cstdlib>
#include <algorithm>
using namespace std;


int main()
{
	int i=0, j=0, holder, offset;
	vector<int> years;
	vector<int> id;
	string sex[10];
	float wage[10];
	int yearsworked, selection;
	
    ifstream infile;
    ofstream outfile;
    
    string disp1, disp2, filename, line;
    
    char selection2, selection3, selection4;
    
    // -----------------  Begin program body ----------------------------------

    cout << "Please input the name of the file you wish to open: " ;
    getline(cin, filename);
    bool found;
    
    infile.open(filename.c_str());
    if(infile.fail())
    {
                      cout <<"\nThe file was not successfully opened." << endl;
                      exit(1);
    }
    
    //Parsing
    while(getline(infile,line))
    {
         int s1 = line.find(" ");
         int s2 = line.find(" ");
         int s3 = line.find(" ");
         
         id.push_back(atoi(line.substr(0, s1).c_str()));
         sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str();
         wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str());
         years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str());
         
         i++;
    }
    
    infile.close();
    
    cout << "The file contained the following:" << endl << endl;
    
	cout <<"Employee ID       " << "Employee Sex         " << "Numeric Wage        "  
         << "Years with Company" << endl;
	cout << "-----------       " << "------------         " 
         << "------------        " << "------------------" << endl;

	for(j=0; j<2; j++)
	{
		cout << setw(11) << right << id[j] << "       "	<< setw(12) << sex[j] << "         " << "$  " 
             << setw(9) << fixed << setprecision(2) << right << wage[j] << "        " 
             << setw(18) <<	right << years[j] << endl;
	}
	vector<int> idcopy(id);
	sort(idcopy.begin(), idcopy.end());
    
    more: //for goto
         
    cout << "\nTo change the hourly wage or years with the company ";
    cout << "for an employee, please enter the ID # from above: ";
	cin >> selection;
	cin.ignore();
	
	
	found = binary_search(idcopy.begin(),idcopy.end(), selection);
	

	while(!found)
    {
                 cout << "\nThe Employee ID No: " << selection <<" was not found." 
                      << "\nPlease select another from the list provided:" ;
                 cin >> selection;
                 cin.ignore();
                 found = binary_search(idcopy.begin(),idcopy.end(), selection);
                      
    }
	
     cout <<"\nEmployee ID       " << "Employee Sex         " << "Numeric Wage        "  
          << "Years with Company" << endl;
     cout << "-----------       " << "------------         " 
          << "------------        " << "------------------" << endl;
                 
     offset = find(id.begin(),id.end(), selection);

	system("PAUSE");
	return 0;
}

Besides the crash, (which i'm almost certain you're correct that it is an array issue, i just don't know how to fix it) the last line gives an error.

(Toggle Plain Text)

offset = find(id.begin(),id.end(), selection);

error: cannot convert `__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >' to `int' in assignment.

I've got another whole half to this program after that line, but like i said, it has to deal with making changes to the data brought in from the file. The other half would work if I could get the offset to work (and NOT CRASH in the first place), since changing the data is based on that offset!!!

daWei, if i'm a pain in your ass, please forgive me b/c I am definitely you're biggest fan and you have definitely kept this alive for me!

Apr 11th, 2006, 2:40 AM	#21
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	OMGBBQ111elevenHashbang David, your function and variable names are catAssTrophicly BadStard. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Apr 11th, 2006, 1:48 PM	#23
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	The only difference between a class and a structure in C++ is that the structure is by default public, and the class is by default private. I would have used a structure, but I decided AFTER making the class to make it public and avoid writing the getter/setter methods. It isn't a good idea, generally, but it was a short example. You'll note how simple it is to make a class -- it almost looks like a function with no code and local variables. Note that, unlike a function, it has to be followed by a semicolon. The class/structure does NOT generate code, typically. It is a pattern for an object that is later created by instantiating it. "bastardRecord theData;" makes one. Another one is made each time I copy theData into a vector. Objects scare a lot of people because self-appointed high-priest/gurus like to gold-plate their mantles and make acolytes kiss their asses. A lawnmower is an object. Mowing the lawn is procedural. Big deal. You might want to read the little blurb in my signature, "OOD, My View". Properly used, it's a helluva tool. Ruben, when I write code for myself, I can be as informal as I like . __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers Last edited by DaWei; Apr 11th, 2006 at 2:11 PM.

Apr 11th, 2006, 3:05 PM	#25
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	And while you are still reading this thread, I've done the reformatting so that the file only saves as raw data with a single space between data. I'm trying to write the program that will read in the file and let you change the data, so as i'm reading it in from the file line by line, i'm splitting it up on the spaces, and funneling them into their respective arrays: BUT, i've got an error on one of them: Please take a look: (Toggle Plain Text) #include <iostream> #include <fstream> #include <string> #include <cctype> #include <iomanip> #include <vector> #include <cstdlib> using namespace std; int main() { int i=0,j=0,id[10]; vector<int> years; char sex[10]; float wage[10]; int yearsworked; ifstream infile; ofstream outfile; string disp1, disp2, filename; string line; cout << "Please input the name of the file you wish to open: " ; getline(cin, filename); infile.open(filename.c_str()); if(infile.fail()) { cout <<"\nThe file was not successfully opened." << endl; exit(1); } //Parsing while(getline(infile,line)) { int s1 = line.find(" "); int s2 = line.find(" "); int s3 = line.find(" "); id[i] = atoi(line.substr(0, s1).c_str()); sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str()); years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str()); i++; } infile.close(); system("PAUSE"); return 0; } #include <iostream> #include <fstream> #include <string> #include <cctype> #include <iomanip> #include <vector> #include <cstdlib> using namespace std; int main() { int i=0,j=0,id[10]; vector<int> years; char sex[10]; float wage[10]; int yearsworked; ifstream infile; ofstream outfile; string disp1, disp2, filename; string line; cout << "Please input the name of the file you wish to open: " ; getline(cin, filename); infile.open(filename.c_str()); if(infile.fail()) { cout <<"\nThe file was not successfully opened." << endl; exit(1); } //Parsing while(getline(infile,line)) { int s1 = line.find(" "); int s2 = line.find(" "); int s3 = line.find(" "); id[i] = atoi(line.substr(0, s1).c_str()); sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str()); years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str()); i++; } infile.close(); system("PAUSE"); return 0; } There error is: invalid conversion from `const char*' to `char' corresponds to : (Toggle Plain Text) sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); What's the fix for this? After that, I'm going to let the users change certain data, but I gotta have the data first!!!

Apr 11th, 2006, 3:17 PM	#26
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	You can't assign a c-string to a single character, which is what sex [index] is. I cautioned you earlier to forget treating gender as a single character, because it limits your options. I don't understand why you're regressing to (forgive me) trash code. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Apr 11th, 2006, 5:50 PM	#29
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Post your new code. You may be overflowing an array, which is why you should be using vectors. You have no idea what the size of the file may be (in a practical world), so you're always going to have problems allocating. Failure to put the items into a structure that aggregates them destroys the interrelationship that they naturally possess. You don't need to search the line for the separator; that's what the various input methods are for. The separator is probably better if it's a non-space (like a comma). You might introduce a name field and want "Joe Bob" to be one item. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Apr 11th, 2006, 1:24 PM	#22
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	So you made the class and used it as a structure, not worrying about defining class methods and made the variables public. Does making the class variables public allow you to do whatever you want with them?

Apr 11th, 2006, 2:18 PM	#24
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	I have read both your view and the thing on pointers, and not only is the pointer page funny, but it's probably the clearest and most illustrative explanation that i've ever seen... And I know that i've asked you before, wise ol' man, but what have you done career-wise to gain such experience with your computer languages?

Apr 11th, 2006, 3:21 PM	#27
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	no, please forgive me..lol.. Through the lengthy posts i forgot to change it to a string, which I did. It now compiles but crashes after completion......................

Apr 11th, 2006, 5:15 PM	#28
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	I've continued building onto the program, but I would like someone to explain to me why it crashes before I post newer, longer code to make the issue more confusing. Thanks!

Apr 11th, 2006, 6:02 PM	#30
codylee270 Unverified User Join Date: Sep 2005 Posts: 209 Rep Power: 0	Alrighty, I know it's long, but i've been building on it. I've got a lot more on the end of it for saving the file, but i'll take it off just for the sake of length (even though its drawn out already. I've got an another few errors, and I'm thinking they all stem from the initial error. I'll elaborate below: (Toggle Plain Text) #include <iostream> #include <fstream> #include <string> #include <cctype> #include <iomanip> #include <vector> #include <cstdlib> #include <algorithm> using namespace std; int main() { int i=0, j=0, holder, offset; vector<int> years; vector<int> id; string sex[10]; float wage[10]; int yearsworked, selection; ifstream infile; ofstream outfile; string disp1, disp2, filename, line; char selection2, selection3, selection4; // ----------------- Begin program body ---------------------------------- cout << "Please input the name of the file you wish to open: " ; getline(cin, filename); bool found; infile.open(filename.c_str()); if(infile.fail()) { cout <<"\nThe file was not successfully opened." << endl; exit(1); } //Parsing while(getline(infile,line)) { int s1 = line.find(" "); int s2 = line.find(" "); int s3 = line.find(" "); id.push_back(atoi(line.substr(0, s1).c_str())); sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str()); years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str()); i++; } infile.close(); cout << "The file contained the following:" << endl << endl; cout <<"Employee ID " << "Employee Sex " << "Numeric Wage " << "Years with Company" << endl; cout << "----------- " << "------------ " << "------------ " << "------------------" << endl; for(j=0; j<2; j++) { cout << setw(11) << right << id[j] << " " << setw(12) << sex[j] << " " << "$ " << setw(9) << fixed << setprecision(2) << right << wage[j] << " " << setw(18) << right << years[j] << endl; } vector<int> idcopy(id); sort(idcopy.begin(), idcopy.end()); more: //for goto cout << "\nTo change the hourly wage or years with the company "; cout << "for an employee, please enter the ID # from above: "; cin >> selection; cin.ignore(); found = binary_search(idcopy.begin(),idcopy.end(), selection); while(!found) { cout << "\nThe Employee ID No: " << selection <<" was not found." << "\nPlease select another from the list provided:" ; cin >> selection; cin.ignore(); found = binary_search(idcopy.begin(),idcopy.end(), selection); } cout <<"\nEmployee ID " << "Employee Sex " << "Numeric Wage " << "Years with Company" << endl; cout << "----------- " << "------------ " << "------------ " << "------------------" << endl; offset = find(id.begin(),id.end(), selection); system("PAUSE"); return 0; } #include <iostream> #include <fstream> #include <string> #include <cctype> #include <iomanip> #include <vector> #include <cstdlib> #include <algorithm> using namespace std; int main() { int i=0, j=0, holder, offset; vector<int> years; vector<int> id; string sex[10]; float wage[10]; int yearsworked, selection; ifstream infile; ofstream outfile; string disp1, disp2, filename, line; char selection2, selection3, selection4; // ----------------- Begin program body ---------------------------------- cout << "Please input the name of the file you wish to open: " ; getline(cin, filename); bool found; infile.open(filename.c_str()); if(infile.fail()) { cout <<"\nThe file was not successfully opened." << endl; exit(1); } //Parsing while(getline(infile,line)) { int s1 = line.find(" "); int s2 = line.find(" "); int s3 = line.find(" "); id.push_back(atoi(line.substr(0, s1).c_str())); sex[i] = line.substr(s1+1, s2 - (s1+1)).c_str(); wage[i] = atoi(line.substr(s2+1, s3 - (s2+1)).c_str()); years[i] = atoi(line.substr(s3+1, line.length()-(s3+1)).c_str()); i++; } infile.close(); cout << "The file contained the following:" << endl << endl; cout <<"Employee ID " << "Employee Sex " << "Numeric Wage " << "Years with Company" << endl; cout << "----------- " << "------------ " << "------------ " << "------------------" << endl; for(j=0; j<2; j++) { cout << setw(11) << right << id[j] << " " << setw(12) << sex[j] << " " << "$ " << setw(9) << fixed << setprecision(2) << right << wage[j] << " " << setw(18) << right << years[j] << endl; } vector<int> idcopy(id); sort(idcopy.begin(), idcopy.end()); more: //for goto cout << "\nTo change the hourly wage or years with the company "; cout << "for an employee, please enter the ID # from above: "; cin >> selection; cin.ignore(); found = binary_search(idcopy.begin(),idcopy.end(), selection); while(!found) { cout << "\nThe Employee ID No: " << selection <<" was not found." << "\nPlease select another from the list provided:" ; cin >> selection; cin.ignore(); found = binary_search(idcopy.begin(),idcopy.end(), selection); } cout <<"\nEmployee ID " << "Employee Sex " << "Numeric Wage " << "Years with Company" << endl; cout << "----------- " << "------------ " << "------------ " << "------------------" << endl; offset = find(id.begin(),id.end(), selection); system("PAUSE"); return 0; } Besides the crash, (which i'm almost certain you're correct that it is an array issue, i just don't know how to fix it) the last line gives an error. (Toggle Plain Text) offset = find(id.begin(),id.end(), selection); offset = find(id.begin(),id.end(), selection); error: cannot convert `__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >' to `int' in assignment. I've got another whole half to this program after that line, but like i said, it has to deal with making changes to the data brought in from the file. The other half would work if I could get the offset to work (and NOT CRASH in the first place), since changing the data is based on that offset!!! daWei, if i'm a pain in your ass, please forgive me b/c I am definitely you're biggest fan and you have definitely kept this alive for me!

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Programming Forums > Application Development > C++

More fileopen close stuff extending from my last thread!