hex dump program

[DamagePlan]

Okay so I have a project due in a class that we have never written a program in and never covered any programming, fortunately I know a little C++. I've searched for examples and haven't come up with much I can make sense of.

Here's the assignment.

You will write a file dump program. It is to take one command line argument: the file to dump. It is to send the contents of the file to the standard output in the following format: each line consists of the byte offset (in hex) of the first byte in the line, followed by a colon, followed by 16 bytes of information as a list of two hex digit blank-separated
hex value, followed by the same 16 bytes as characters if they are printable [in the range 0x20-0x7e] or as a dot if they are not printable.

I really have no idea what I'm doing, I'm not asking anyone to write this whole thing for me just help one a little at a time. Right now if I just try and compile my program it compiles but if I try and give it a file name it tells me.

using: Command not found
Badly placed ()'s 

Here's my program so far

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

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

ofstream file;
file.open(argv[1]);

}

[DamagePlan]

I think I fixed that I was doing

main test.txt

instead of

a.out test.txt

How do I get the byte offset stuff and print in 2 hex char chunks?

[hamsterman]

You'll have to read 16 bytes from your file( http://www.cplusplus.com/reference/iostream/istream/read/ ). Then get the offset int the file (http://www.cplusplus.com/reference/iostream/istream/tellg/ ,I think). Then for each byte convert it to hex and print it. Then agin for each byte check if they are in the required range an if so print them as chars ,else print '.'.
Repeat this process until you reach the end of file.
Specify, which part of this is unclear.