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Sep 24th, 2006

first cannot conver std::string to const char, now runtime error!

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C++ Syntax (Toggle Plain Text)
cin.ignore();
cout << "Enter lecture notes/tutorials location.\n";
cout << "e.g C:/Lecture Notes/lecture01.ppt";
cout << ">>>";
getline(cin,lectut_loca);
cout << "Enter lecture notes/tutorials name: ";
cout << "e.g lecture01.ppt";
cout << ">>>";
getline(cin,lectut_name);
string copy = "copy";
copier = copy + " " + lectut_loca + " " + lectut_name;
const char *copier;
cout << copier;
getch();
system(copier);
cout << "\nLecture notes/tutorials added.";
cin.ignore();
cout << "Enter lecture notes/tutorials location.\n";
cout << "e.g C:/Lecture Notes/lecture01.ppt";
cout << ">>>";
getline(cin,lectut_loca);
cout << "Enter lecture notes/tutorials name: ";
cout << "e.g lecture01.ppt";
cout << ">>>";
getline(cin,lectut_name);
string copy = "copy";
copier = copy + " " + lectut_loca + " " + lectut_name;
const char *copier;
cout << copier;
getch();
system(copier);
cout << "\nLecture notes/tutorials added.";

the const char *copier; i use copier = copier.c_str(); but get error on system(copier); when compiling. then i use const char *copier; no error compile but runtime error!

:lol:

what should i do?

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converting std::string to const chars? in C++

n3st3d_l00p

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

Click to Expand / Collapse Quote originally posted by n3st3d_l00p ...

(Toggle Plain Text)
cin.ignore();
cout << "Enter lecture notes/tutorials location.\n";
cout << "e.g C:/Lecture Notes/lecture01.ppt";
cout << ">>>";
getline(cin,lectut_loca);
cout << "Enter lecture notes/tutorials name: ";
cout << "e.g lecture01.ppt";
cout << ">>>";
getline(cin,lectut_name);
string copy = "copy";
 copier = copy + " " + lectut_loca + " " + lectut_name;
// using variable before declaring it is not allowed in your case copier.

 const char *copier; // initialisation of const variables must be done 
                            // during declaration intself eg. const int i = 8 ;
 cout << copier;
 getch(); // getch() is non portable use cin.get ()
system(copier);
cout << "\nLecture notes/tutorials added.";
cin.ignore(); cout << "Enter lecture notes/tutorials location.\n"; cout << "e.g C:/Lecture Notes/lecture01.ppt"; cout << ">>>"; getline(cin,lectut_loca); cout << "Enter lecture notes/tutorials name: "; cout << "e.g lecture01.ppt"; cout << ">>>"; getline(cin,lectut_name); string copy = "copy"; copier = copy + " " + lectut_loca + " " + lectut_name; // using variable before declaring it is not allowed in your case copier. const char *copier; // initialisation of const variables must be done // during declaration intself eg. const int i = 8 ; cout << copier; getch(); // getch() is non portable use cin.get () system(copier); cout << "\nLecture notes/tutorials added.";
what should i do?

Look at the things i have mentioned above.
And maybe you should look at this simple expample.

C++ Syntax (Toggle Plain Text)
string my_copy = "copy" ;
my_copy += " " + lectut_loca + " " + lectut_name ;
const char* copier = my_copy.c_str() ;
system (copier) ;
string my_copy = "copy" ;
my_copy += " " + lectut_loca + " " + lectut_name ;
const char* copier = my_copy.c_str() ;
system (copier) ;

Hope ti helped, bye.

PS: looks like you are trying to implement the copy function of DOS.

~s.o.s~

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

Click to Expand / Collapse Quote originally posted by ~s.o.s~ ...

Look at the things i have mentioned above.
And maybe you should look at this simple expample.
C++ Syntax (Toggle Plain Text)
string my_copy = "copy" ;
my_copy += " " + lectut_loca + " " + lectut_name ;
const char* copier = my_copy.c_str() ;
system (copier) ;
string my_copy = "copy" ; my_copy += " " + lectut_loca + " " + lectut_name ; const char* copier = my_copy.c_str() ; system (copier) ;
Hope ti helped, bye.

PS: looks like you are trying to implement the copy function of DOS.

yah.. should be like that? urmm.. syntax error!

n3st3d_l00p

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

add

char a='"';
strcat(a, copier);
strcat(copier, a);

hahaha.. compile error!

n3st3d_l00p

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

I dont get you...
Are you saying even after making the changes you get a syntax error ???

~s.o.s~

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

Error messages come with line numbers.
Use those line numbers to find out where in the code the problem is. Any editor should have a "goto line" feature, or at least display line numbers in some manner.

Post code (annotated with line numbers if necessary) along with exact error messages if you're still stuck.

Salem

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

yes.. after making the change.

error in runtime.. The syntax of the command is incorrect.

n3st3d_l00p

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

Click to Expand / Collapse Quote originally posted by n3st3d_l00p ...

add

char a='"';
strcat(a, copier);
strcat(copier, a);

hahaha.. compile error!

Umm... buddy, what exactly are you trying to do.
strcat funtion expects you to supply both parameters as char* ie char pointers and you supplying it a char.

You can get its prototype here: http://www.cppreference.com

Post your complete program from start to finish with the header files and then maybe i could pinpoint the mistake.

~s.o.s~

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

the staff module...

C++ Syntax (Toggle Plain Text)
//the staff module
 
#include "staff.h"
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
 
class sfunction
{
      private:
              string lectut_loca;
              string lectut_id;
              string lectut_name;
 
              string announce_id;
              string announce_subject;
              string announce_desc;
 
      public:
             void add_lec_tut()
             {
                  string copier;
                  display_title("Add Lecture Notes/Tutorials");
                  cout << "Please enter course id: ";
                  cin >> lectut_id;
                  for(int i=1; i<=count_line("course.MOLS"); i++)
                  {
                          if(gettok( read("course.MOLS", i), ';', 1) == lectut_id)
                          {
                               cin.ignore();
                               cout << "Enter lecture notes/tutorials location.\n";
                               cout << "e.g C:/Lecture Notes/lecture01.ppt";
                               cout << ">>>";
                               getline(cin,lectut_loca);
                               cout << "Enter lecture notes/tutorials name: ";
                               cout << "e.g lecture01.ppt";
                               cout << ">>>";
                               getline(cin,lectut_name);
                               string my_copy = "copy" ;
                               my_copy += " " + lectut_loca + " " + lectut_name ;
                               const char* copier = my_copy.c_str() ;
                               cout << copier;
                               system(copier);
                               cin.get();                               
                               cout << "\nLecture notes/tutorials added.";
                               getch(); break;
                          }
                          else if(i==count_line("course.MOLS"))
                          {
                               cout << lectut_id << " not found!";
                               getch();
                          }
                  }
 
 
 
                  getch();
 
             };
             void edit_lec_tut()
             {
                  display_title("Edit Lecture Notes/Tutorials");
                  getch();
             };
             void del_lec_tut(){};
 
             void add_announ()//add announcement(s)
             {
                  display_title("Add Announcements");
                  cout << "Please enter course id: ";
                  cin >> announce_subject;
                  for(int i=1; i<=count_line("course.MOLS"); i++)
                  {
                          if(gettok( read("course.MOLS", i), ';', 1) == announce_subject)
                          {
                               cout << "Plase enter announcement id: ";
                               cin >> announce_id;
                               cin.ignore();
                               cout << "Please enter your announcement: ";
                               getline(cin,announce_desc);
                               write("Lecturer/announcement.MOLS", i, announce_id + ";" + announce_subject + ";" + announce_desc);
                               cout << "\nAnnouncement added.";
                               getch(); break;
                          }
                          else if(i==count_line("course.MOLS"))
                          {
                               cout << announce_subject << " not found!";
                               getch();
                          }
                  }
             };
 
             void edit_announ()
             {
                  display_title("Add Announcements");
                  cout << "Enter course id: ";
                  cin >> announce_subject;
                  for(int i=1; i<=count_line("Lecturer/announcement.MOLS"); i++)
                  {
                          if(gettok( read("Lecturer/announcement.MOLS", i), ';', 2) == announce_subject)
                          {
                               cout << "Previous announcement:\n"
                               << gettok( read("Lecturer/announcement.MOLS", i), ';', 3) << endl;
                               cout << "\nEnter new announcement id: ";
                               cin >> announce_id;
                               cin.ignore();
                               cout << "Enter new announcement: ";
                               getline(cin,announce_desc);
                               write("Lecturer/announcement.MOLS", i, announce_id + ";" + announce_subject + ";" + announce_desc);
                               cout << "\nAnnouncement added.";
                               getch(); break;
                          }
                          else if(i==count_line("Lecturer/announcement.MOLS"))
                          {
                               cout << announce_subject << " not found!";
                               getch();
                          }
                  }
             };
             void del_announ()
             {
                  display_title("Delete Announcements");
                  cout << "Enter announcement id: ";
                  cin >> announce_id;
                  for(int i=1; i<=count_line("Lecturer/announcement.MOLS"); i++)
                  {
                          if(gettok( read("Lecturer/announcement.MOLS", i), ';', 1) == announce_id)
                          {
                                     del("Lecturer/announcement.MOLS", i);
                                     cout << "Announcement succesfully deleted!";
                                     getch();
                          }
                  }
             };
             void add_assign(){};
             void edit_assign(){};
             void del_assign(){};
};
//the staff module

#include "staff.h"
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;

class sfunction
{
      private:
              string lectut_loca;
              string lectut_id;
              string lectut_name;
              
              string announce_id;
              string announce_subject;
              string announce_desc;
              
      public:
             void add_lec_tut()
             {
                  string copier;
                  display_title("Add Lecture Notes/Tutorials");
                  cout << "Please enter course id: ";
                  cin >> lectut_id;
                  for(int i=1; i<=count_line("course.MOLS"); i++)
                  {
                          if(gettok( read("course.MOLS", i), ';', 1) == lectut_id)
                          {
                               cin.ignore();
                               cout << "Enter lecture notes/tutorials location.\n";
                               cout << "e.g C:/Lecture Notes/lecture01.ppt";
                               cout << ">>>";
                               getline(cin,lectut_loca);
                               cout << "Enter lecture notes/tutorials name: ";
                               cout << "e.g lecture01.ppt";
                               cout << ">>>";
                               getline(cin,lectut_name);
                               string my_copy = "copy" ;
                               my_copy += " " + lectut_loca + " " + lectut_name ;
                               const char* copier = my_copy.c_str() ;
                               cout << copier;
                               system(copier);
                               cin.get();                               
                               cout << "\nLecture notes/tutorials added.";
                               getch(); break;
                          }
                          else if(i==count_line("course.MOLS"))
                          {
                               cout << lectut_id << " not found!";
                               getch();
                          }
                  }
                  
                  
                  
                  getch();
                  
             };
             void edit_lec_tut()
             {
                  display_title("Edit Lecture Notes/Tutorials");
                  getch();
             };
             void del_lec_tut(){};
             
             void add_announ()//add announcement(s)
             {
                  display_title("Add Announcements");
                  cout << "Please enter course id: ";
                  cin >> announce_subject;
                  for(int i=1; i<=count_line("course.MOLS"); i++)
                  {
                          if(gettok( read("course.MOLS", i), ';', 1) == announce_subject)
                          {
                               cout << "Plase enter announcement id: ";
                               cin >> announce_id;
                               cin.ignore();
                               cout << "Please enter your announcement: ";
                               getline(cin,announce_desc);
                               write("Lecturer/announcement.MOLS", i, announce_id + ";" + announce_subject + ";" + announce_desc);
                               cout << "\nAnnouncement added.";
                               getch(); break;
                          }
                          else if(i==count_line("course.MOLS"))
                          {
                               cout << announce_subject << " not found!";
                               getch();
                          }
                  }
             };
             
             void edit_announ()
             {
                  display_title("Add Announcements");
                  cout << "Enter course id: ";
                  cin >> announce_subject;
                  for(int i=1; i<=count_line("Lecturer/announcement.MOLS"); i++)
                  {
                          if(gettok( read("Lecturer/announcement.MOLS", i), ';', 2) == announce_subject)
                          {
                               cout << "Previous announcement:\n"
                               << gettok( read("Lecturer/announcement.MOLS", i), ';', 3) << endl;
                               cout << "\nEnter new announcement id: ";
                               cin >> announce_id;
                               cin.ignore();
                               cout << "Enter new announcement: ";
                               getline(cin,announce_desc);
                               write("Lecturer/announcement.MOLS", i, announce_id + ";" + announce_subject + ";" + announce_desc);
                               cout << "\nAnnouncement added.";
                               getch(); break;
                          }
                          else if(i==count_line("Lecturer/announcement.MOLS"))
                          {
                               cout << announce_subject << " not found!";
                               getch();
                          }
                  }
             };
             void del_announ()
             {
                  display_title("Delete Announcements");
                  cout << "Enter announcement id: ";
                  cin >> announce_id;
                  for(int i=1; i<=count_line("Lecturer/announcement.MOLS"); i++)
                  {
                          if(gettok( read("Lecturer/announcement.MOLS", i), ';', 1) == announce_id)
                          {
                                     del("Lecturer/announcement.MOLS", i);
                                     cout << "Announcement succesfully deleted!";
                                     getch();
                          }
                  }
             };
             void add_assign(){};
             void edit_assign(){};
             void del_assign(){};
};

and the staff header

C++ Syntax (Toggle Plain Text)
#ifndef    _STAFF_H_
#define    _STAFF_H_
#include "staff.cpp"
#endif
#ifndef    _STAFF_H_
#define    _STAFF_H_
#include "staff.cpp"
#endif

n3st3d_l00p

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Sep 24th, 2006

Re: first cannot conver std::string to const char, now runtime error!

So where is your int main (void) function and what problems are you facing with this code, and if facing compile time problems mark the line which flags the error in red so taht we can see it and if run time error then describe it.

~s.o.s~

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