Creating files

Please can anyone tell me what is wrong with this function.I am trying to create a text file but its not working

Code:

void Grades ::createFile(){
  string s;
string filename;
cout<<"please enter the name you want to name your file";
cin>>filename;

cout<<"please enter the text you want to create";
    cin>>s;
    ofstream mfile;
  mfile.open(filename);
  mfile<<s;
  mfile.close();
}

You need to use filename.c_str() in your open call.

Originally Posted by oogabooga

You need to use filename.c_str() in your open call.

I dont know what you mean by open call.

This line

Code:

 mfile.open(filename);

should be this

Code:

 mfile.open(filename.c_str());

Also, it would be better to read the filename and the text to write to the file with getline, like this:

Code:

getline(cin, filename);

"call" is what you say or how you describe it when you use a function, in your code; be it your own or one in a library.

Code:

#include <iostream>

using namespace std;

void MyFunction() //declare it - this is the simplest example.
{

	cout << "I called MyFunction()...!!!\n";
}

int main()
{
	cout << "I am about to call MyFunction, .... lock up your daughters!\n";
	MyFunction(); 	//call it
	
	return 0;
}

Equally when your code has " myString.c_str() " you called a member function (member of the class string) that returns a null terminated c-style string.

Could also turn on C++0x support - if your compiler has support, using the switch will compile your code as is. Look:

Code:

#include <fstream>
#include <iostream>
#include <string>

using namespace std;

int main()
{
    string s;
    string filename;
    cout<<"please enter the name you want to name your file";
    cin>>filename;

    cout<<"please enter the text you want to create";
    cin>>s;
    ofstream mfile;
    mfile.open(filename);
    mfile<<s;
    mfile.close();
}

/* 
mingw32-g++.exe -std=c++0x -Wall  -g     -c "C:\Documents and Settings\User\My Documents\sandbox\sandbox.cpp" -o obj\Debug\sandbox.o
Process terminated with status 0 (0 minutes, 0 seconds)
0 errors, 0 warnings
*/

Neat right?

Originally Posted by whiteflags

Could also turn on C++0x support - if your compiler has support, using the switch will compile your code as is. Look:

Code:

#include <fstream>
#include <iostream>
#include <string>

using namespace std;

int main()
{
    string s;
    string filename;
    cout<<"please enter the name you want to name your file";
    cin>>filename;

    cout<<"please enter the text you want to create";
    cin>>s;
    ofstream mfile;
    mfile.open(filename);
    mfile<<s;
    mfile.close();
}

/* 
mingw32-g++.exe -std=c++0x -Wall  -g     -c "C:\Documents and Settings\User\My Documents\sandbox\sandbox.cpp" -o obj\Debug\sandbox.o
Process terminated with status 0 (0 minutes, 0 seconds)
0 errors, 0 warnings
*/

Neat right?

interesting would try it out and find out how it goes

These two can also be merged:

ofstream mfile;
mfile.open(filename);

ofstream mfile(filename);

And this

mfile.close();

is just plain unnecessary. The destructor will automatically call close.