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:

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

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)

I dont know how to get it to work!

Code:

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#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;

}

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Code:

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

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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:

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

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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

Quote:

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Originally Posted by edoceo

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

Code:

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

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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

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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:

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

delete p;

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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:

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

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Quote:

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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:

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

delete p;

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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.

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

Quote:

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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:

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

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tanx.

Quote:

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Originally Posted by edoceo

Code:

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

delete p;

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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:

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

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

Code:

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

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Now you're talking!

Quote:

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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:

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

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

Code:

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

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Now you're talking!

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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.