Input-Output File--Can't create a file...

I use following syntax to create a file but file can't be created

Code:

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path1 = "D:\\Example\InputFile.txt";
fstream InOutFile(path1,ios::in|ios::out);
        if (!InOutFile){
                cerr<<"File can't be created!"<<endl;
                exit(1);
        }

---

When InOutFile is false??I can't create a file because InOutFile is always false...?Why?Please help me , thanks very much....
I declared suitable librarys....And compiling doesn't have any errors

>> D:\\Example\InputFile.txt
Should be D:\\Example\\InputFile.txt.

Quote:

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compiling doesn't have any errors

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Turn up your warning levels. (-W -Wall for GCC.) You should get a message like "unknown escape sequence `\I'", unless \I is a compiler extension and therefore does exist. (Compilers are free to make uppercase escape sequences do what they want.)

[edit] Instead of using fstream, use ifstream, for input file stream. [/edit]

[edit=2] CProgramming.com Tutorial: Lesson 10: C++ File I/O [/edit]

>> Instead of using fstream, use ifstream, for input file stream.
The OP is pretty clearly trying to open the file for both input and output, which requires fstream.

Oops, I missed that. Maybe I should read the tutorial. :p

Quote:

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Originally Posted by Daved

>> D:\\Example\InputFile.txt
Should be D:\\Example\\InputFile.txt.

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I'm using Visual C++ Express Edition..
I remain have this error...this is my full code:

"ClassType.h"

Code:

---

#ifndef CLASSTYPE_H
#define CLASSTYPE_H
#include "TypeData.h"
#include <fstream>
using namespace std;

class Data{
public:
        void duongdan1(char * );

        void duongdan2(char * );

        void NhapChoice();
        void TextFile(fstream&);
        void UpdateRecord(fstream&);
        void NewRecord(fstream&);
        void DeleteRecord(fstream&);
        void OutputLine(ostream&,const TypeData&);
        int getAccount(const char*);
private:
        int choice;
        char * path1,*path2;
};

#endif

---

"TypeData.h"

Code:

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#ifndef TYPEDATA_H
#define TYPEDATA_H
struct TypeData{
        int accountName;
        char name[100];
        double balance;
};
#endif

---

"ClassType.cpp"

Code:

---

#ifndef CLASSTYPE_CPP
#define CLASSTYPE_CPP
#include "ClassType.h"
#include <iostream>
#include <iomanip>
using namespace std;

void Data::duongdan1(char * dd1){
        path1 = dd1;
}


void Data::duongdan2(char * dd2){
        path2 = dd2;
}

void Data::NhapChoice(){
        fstream XuatNhapFile(path1,ios::in|ios::out);
        if (!XuatNhapFile){
                cerr<<"File khong the tao!"<<endl;
                exit(1);
        }

        cout<<"\nNhap lua chon cua ban\n"
                <<"1 - Du Tru 1 dinh dang file text\n"
                <<"2 - Cap nhat 1 tai khoan moi\n"
                <<"3 - Them 1 tai khoan moi\n"
                <<"4 - Xoa 1 tai khoan\n"
                <<"5 - Ket thuc chuong trinh\n";
        cin>>choice;
        while (choice != 5){
                switch(choice){
                        case 1:
                                TextFile(XuatNhapFile);
                                break;
                        case 2:
                                UpdateRecord(XuatNhapFile);
                                break;
                        case 3:
                                NewRecord(XuatNhapFile);
                                break;
                        case 4:
                                DeleteRecord(XuatNhapFile);
                                break;
                        default:
                                cerr<<"Lua chon sai";
                }
                //Reset end of file
                XuatNhapFile.clear();
        }
}

void Data::TextFile(fstream &DocFile){
        ofstream XuatFile(path2,ios::out);
        if (!XuatFile){
                cerr<<"File khong mo duoc!";
                exit(1);
        }
        XuatFile<<setiosflags(ios::left)<<setw(10)
                <<"Account" <<setw(22)<< "Name"
                <<setiosflags(ios::left)
                <<setw(10)<<"Balance"<<endl;
        DocFile.seekg(0);
        TypeData dulieu;
        DocFile.read(reinterpret_cast<char *>(&dulieu),sizeof(TypeData));
        while(!DocFile.eof()){
                if(dulieu.accountName != 0)
                        OutputLine(XuatFile, dulieu);
                DocFile.read(reinterpret_cast <char *>(&dulieu),sizeof(TypeData));
        }
}

void Data::UpdateRecord(fstream &UpdateFile){
        TypeData dulieu;
        int account = getAccount("Nhan 1 tai khoan de update!");
        UpdateFile.seekg((account-1) * sizeof(dulieu));
        UpdateFile.read(reinterpret_cast <char *>(&dulieu),sizeof(TypeData));
        if (dulieu.accountName != 0){
                OutputLine(cout,dulieu);
                cout<<"\nNhan thay doi tang hoac giam!";
                float chuyentai;
                cin>>chuyentai;
                dulieu.balance += chuyentai;
                OutputLine(cout,dulieu);
                UpdateFile.seekp((account-1) * sizeof(dulieu));
                UpdateFile.write(reinterpret_cast<const char *> (&dulieu),sizeof(TypeData));
        }
        else
                cerr<<"Account #"<<account
                <<"has no information."<<endl;
}

void Data::NewRecord(fstream &insertFile){
        TypeData dulieu;
        int account = getAccount("Nhan 1 tai khoan moi!");
        insertFile.seekg((account-1) * sizeof(dulieu));
        insertFile.read(reinterpret_cast <char *>(&dulieu),sizeof(TypeData));
        if(dulieu.accountName == 0){
                cout<<"Nhap name: ";
                cin>>dulieu.name>>dulieu.balance;
                dulieu.accountName = account;
                insertFile.seekp((account-1) * sizeof(dulieu));
                insertFile.write(reinterpret_cast <const char *>(&dulieu), sizeof(TypeData));
        }
        else
                cerr << "Account #" <<account
                <<" already contains information."<<endl;
}

void Data::DeleteRecord(fstream & deleteFile){
        TypeData dulieu;
        int account = getAccount("Nhan 1 tai khoan de xoa!");
        deleteFile.seekg((account-1) * sizeof(dulieu));
        deleteFile.read(reinterpret_cast <char *>(&dulieu),sizeof(TypeData));
        if (dulieu.accountName != 0){
                TypeData dulieu1 = {0,"",0.0};
                deleteFile.seekp((account-1) * sizeof(dulieu));
                deleteFile.write(reinterpret_cast <const char *>(&dulieu1), sizeof(TypeData));
                cout<<"Account #"<<account<<"deleted"<<endl;
        }
        else
                cerr<<"Account #"<<account<<" is empty."<<endl;
}

void Data::OutputLine(ostream &output, const TypeData &c){
        output<<setiosflags(ios::left)<<setw(10)
                <<c.accountName<<setw(22)<<c.name
                <<setw(11)<<setprecision(2)<<resetiosflags(ios::left)
                <<setiosflags(ios::fixed|ios::showpoint)
                <<c.balance<<"\n";
}

int Data::getAccount(const char *nhac){
        int account;
        do{
                cout<<nhac<<"(1 - 100): ";
                cin>>account;
        }while(account<1||account>100);
        return account;
}

#endif

---

"Use.cpp"

Code:

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#include "stdafx.h"
#include "ClassType.h"
#include "TypeData.h"



int _tmain(int argc, _TCHAR* argv[])
{
        Data data;
        char * dd1 = "D:\\Example\\InputFile.txt";
        char * dd2 = "D:\\thu\\OutputFile.txt";

        data.duongdan1(dd1);

        data.duongdan2(dd2);
        data.NhapChoice();
        return 0;
}

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I want to create a text file,input data into this file,then I use a function to read data from that file and process these datas.... After that I want to output data(result) in another text file...what should I do?...

Everybody can tell me a sample code that can be used to do this ? thanks very much.....

> char * path1,*path2;
Are you allowed to use the string class?

Code:

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#include <string>
.
.
        string path1, path2;

---

Otherwise you'll have to allocate memory for path1 and path2 (or change them to char arrays) and use strcpy to copy into them.

sorry,I use declaration:
fstream XuatNhapFile(path1,ios::in|ios:out);
and path1 must be char *
and can you type more clearly about using strcpy to copy them?

I don't think you have to worry about copying them with strcpy since you never change them in the class, although you should make them const char* just to make sure you don't. You can pass around const char* pointers as much as you like as long as you aren't expecting them to change.

However, using the string class is still a good idea. It works fine with fstream, you just have to use the c_str() function: fstream XuatNhapFile(path1.c_str(),ios::in|ios:out);

>> I remain have this error...
Does that mean that the file still doesn't open for you? What if you do try it with just an ifstream without the ios:: flags since it looks like you won't be using that file for output after all?

Quote:

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Originally Posted by Daved

Does that mean that the file still doesn't open for you? What if you do try it with just an ifstream without the ios:: flags since it looks like you won't be using that file for output after all?

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Yes.....It still doesn't create a file....I don't know why....

Does the file exist at that place on your hard drive? Does the following program display success or failure?

Code:

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#include <iostream>
#include <fstream>
using namespace std;

int main()
{
  ifstream inf("D:\\Example\\InputFile.txt");
  if (!inf)
    cout << "Failure!\n";
  else
    cout << "Success!\n";
}

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Since you are using an absolute path, it should work if the file is there on your hard drive. If that isn't the exact string you are using, then maybe you should show us the exact path you are using.