Thread: string variable used as a variable...

So you want to be able to parhaps get a string from the user then use a variable of that name? I don't think thats possible, you cannot 'change' the names of your variables while the program is running (can you?).

Ie

PHP Code:

string name="paul";

string "paul" = "john"; 


Is just illogical.

~ Paul

>>you cannot 'change' the names of your variables while the program is running (can you?).

No.

no.

but try it, it should not compile. .Nice is not a member of string, it is a member of struct Gender.

You can use polymorphism and an object factory which creates objects based on an string.

But that won't be very usefull in your situation. I just like to sound smart.

gg

Thats a totally different question to the one you first asked, but

PHP Code:

string Name;
string fileName;
string ext = ".txt";

cin >> Name;
fileName = Name+ext;         // If you can do that with strings, I havent done this for so long. 
                                            // I know an ansi string you can.
fstream File(fileName); 


It uses the string and data for a variable, NOT as the name of a variable, which is what you had been trying to do previousley.

~ Paul

or u can cut out the middle-man

Code:

 

string name;
string ext = ".txt";

cout << "Enter name for file(no ext included!): ";
cin >> name;

name += ext;

fstream file(name);

also, a simple additon of

Code:

cout<< "Enter the extentions type in format: *.ext* and press enter: ";
cin>>ext;

will let u save as any file.

So if u want a file called test as a doc file you would enter

test

when asked and

.doc

when asked.

I'm not quite sure if it will let you do that. You can try it, though. If it doesn't work, you may want to try using the .c_str() fxn to convert it to a c string, because I believe ifstream takes a c string as the argument:

for example:

Code:

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

int main()
{
	std::string test;
	
	std::cout << "Enter filename (with file type, ex. text.txt): ";
	std::cin >> test;
	
	std::ifstream infile(test.c_str());
	if(!infile) {
		std::cerr << "Error opening " << test << std::endl;
		exit(1);
	} else {
		std::cout << "File open." << std::endl;
	}
	
	return 0;
}

I tried it without the .c_str() fxn, it wouldn't compile. it should be because ifstream takes c strings as arguments in this example.

You can use the suggestions above to let the user have options, just remember, if you want to open the file, and you have the filename stored in a string to use the .c_str() fxn. hope this helps some.

>>I'm not quite sure if it will let you do that

Heres a program i have that does it. Its a few months old so ignore the comments lol.

Code:

#include <iostream>
#include <windows.h>
#include <string>
#include <stdlib.h>

using namespace std;

int find_files();

/*	Define our STD's*/
using std::string;
using std::cout;
using std::cin;
using std::endl;


int main(int argc,char** argv)
{

	find_files();

	system("pause");

	return 0;
	

}

int find_files()
{
	/*	Holds information found*/
	WIN32_FIND_DATA wfd;

	/*	Holds directory*/
	string str,extension;

	str = "";


	/*	Counts files found*/
	int i = 0;

	/*	Prompt user for directory*/
	cout<< "Enter Directory: ";
	cin>>str;

	cout<< "Enter the extentions type in format: *.ext* and press enter: ";
	cin>>extension;

	extension = "\\" + extension;

	/*	Outout empty line*/
	cout<<"\n";

	/*	Indicates we want mp3 files*/
	str += extension;

	/*	Find first file*/	
	HANDLE hFile =  FindFirstFile(str.c_str(),&wfd);

	/*	Aborts on error*/
	if(hFile ==INVALID_HANDLE_VALUE)
	{
		cout<<"No files found or invalid directory\n";
		return 1;
	}

	do
	{
		/*	out files*/
		cout<<wfd.cFileName<<endl;

		/*	Increment counter*/
		i++;	
	}
	
	/*	Get the rest of the files*/
	while(FindNextFile(hFile,&wfd));

	/*	Output # of found files*/
	cout<<"\nFound "<<i<<" Files.\n"<<endl;

	/*	Clean up*/
	FindClose(hFile);

	
	return 0;
}