need help on a primitive problem

hello all, i have problems implementing a path for the following program
well , the prototype says it only accepts , *char and char! no string! so im stuck!
im talking about this (

Code:

std::ifstream f(path, std::ios::binary);

)

I dont know how to get it to work!

Code:

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
int main()
{

         unsigned char c;
         string path;
         char *route;


         cin>>route;
         std::ifstream f(route, std::ios::binary);




         while (f >> c)
        {
                std::cout << std::hex << std::setw(2) << std::setfill('0') << (unsigned int)c <<"  ";//or << (unsigned int)c << "\t"
        }

return 0;

}

Code:

std::ifstream f(route, std::ios::binary);

either This is not working,
it compiles well, but , at run time when you enter a path! and press enter! it crashes! really dont know how to go about it!

you can make your std::string return a valid 'char *' to itself by calling it's <string>.c_str();

Code:

std::string path  ("./my_file.txt");
std::ifstream f (path.c_str(), std::ios::binary);

And about your crashing program: You must initialize your 'char *route' to something and make it point to a valid location for std::cin to write to before calling.. std::cin

Originally Posted by edoceo

you can make your std::string return a valid 'char *' to itself by calling it's <string>.c_str();

Code:

std::string path  ("./my_file.txt");
std::ifstream f (path.c_str(), std::ios::binary);

And about your crashing program: You must initialize your 'char *route' to something and make it point to a valid location for std::cin to write to before calling.. std::cin

thanks alot!
Will char* route = NULL; do it?

No, you will have to make char *route point to a location where you can write data read from stdin (std::cin)

Code:

char *p = new char[1024];
std::cin >> p;
std::cout << "input: " << p << std::endl;

delete p;

But you should use std::string instead of defining your own char-buffers. The above program might not behave the way it should if the user inputs more then 1023 characters! This is because you will write out-of-bounds and might cause memorycorruption.

when you use strings in a char area you should can use the string method c_str();

so you could do

Code:

using namespace std;
...
ifstream fp (path.c_str(), ios::binary);

Originally Posted by edoceo

No, you will have to make char *route point to a location where you can write data read from stdin (std::cin)

Code:

char *p = new char[1024];
std::cin >> p;
std::cout << "input: " << p << std::endl;

delete p;

But you should use std::string instead of defining your own char-buffers. The above program might not behave the way it should if the user inputs more then 1023 characters! This is because you will write out-of-bounds and might cause memorycorruption.

thanks , in case im using the upper and below solutions ( which are the same! ) , is there any reason to initialize the *char var yet?

Originally Posted by mramazing

when you use strings in a char area you should can use the string method c_str();

so you could do

Code:

using namespace std;
...
ifstream fp (path.c_str(), ios::binary);

tanx.

Originally Posted by edoceo

Code:

char *p = new char[1024];
std::cin >> p;
std::cout << "input: " << p << std::endl;

delete p;

That uses the wrong delete operator and you should not needlessly put small things that exist for a small scope on the heap. This is what the stack is for.
This is far better:

Code:

char p[1024];
std::cin >> p;
std::cout << "input: " << p << std::endl;

No chance of a leak now, but you could still get a buffer overrun, and p is a poor variable name.

Code:

std::string route;
std::cin >> route;
std::cout << "input: " << route << std::endl;

Now you're talking!

Originally Posted by iMalc

That uses the wrong delete operator and you should not needlessly put small things that exist for a small scope on the heap. This is what the stack is for.
This is far better:

Code:

char p[1024];
std::cin >> p;
std::cout << "input: " << p << std::endl;

No chance of a leak now, but you could still get a buffer overrun, and p is a poor variable name.

Code:

std::string route;
std::cin >> route;
std::cout << "input: " << route << std::endl;

Now you're talking!

yes, delete[] should have been used. I was in a hurry catching my ride down to Gothenburg (Sweden) (and it was 3:41 am). no sleep for 38 hours + stress = bad combination

And since OP wanted to initiate a 'char *' I wrote an example using just that.