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Control Flow

2 (2.2%)

Arrays, Strings, Pointers, and References

8 (9%)

Functions

4 (4.5%)

Basic object-oriented programming

30 (33.7%)

A bit more advanced OOP (Composition, Operator overloading, Inheritance, Virtual Functions)

18 (20.2%)

Templates

8 (9%)

Other (Explain)

4 (4.5%)

Working with files?  (Streams)

15 (16.9%)

Total Members Voted: 89

[ILikePie]

Hm. That's great. So, to give access to the database to a user on a different computer, I'll need a way to put the ElementsData into their home directory...

Getting the application's directory shouldn't be to hard. The full path to application is stored in argv[0], just save it as a string.

Oh... Why? Does it need it? The math library required by "math.h"?

It's kind of silly really. For some reason, you don't need the -lm flag on Windows, all you need to #include <math.h>. Seems to be a Linux thing.

[lordnincompoop]

Been a while since I passed data like that Try

int IO(char** cReturnValue[10]) for your function declaration.

Thanks, I think I fixed it.

[Supermikhail]

Hm. That's great. So, to give access to the database to a user on a different computer, I'll need a way to put the ElementsData into their home directory...

Getting the application's directory shouldn't be to hard. The full path to application is stored in argv[0], just save it as a string.

Oh... Why? Does it need it? The math library required by "math.h"?

It's kind of silly really. For some reason, you don't need the -lm flag on Windows, all you need to #include <math.h>. Seems to be a Linux thing.

Can you say how reliable argv[0] is? Google seems to think that it can be pretty random, depending on where and how the application was launched.

On another note, I'm so tired of this bullshit (including not-reading files) that I'm even considering changing the language. Anyone can suggest what I could kind of easily transfer my... newly-acquired knowledge of C++ into? I don't exactly have a lot of time to dawdle around, so even if I solve my current problems, am I going to have to jump through hoops with the intricacies of C++ the rest of the way?

I'm considering going back to Object Pascal, as I programmed in it... like 5 years ago. But I haven't been able to find any good educational sources to supplement my beginner book, and Delphi books I've seen deal mostly with databases which is not exactly up my valley.

[lordnincompoop]

There's C-Sharp, or D. Hell, even Python. Any C relative will to, AFAIK.

I eliminated the errors and all I get are warnings about strtok being depreciated. But when I run it, immediately after it posts the room description it crashes. What am I doing wrong?

Code: [Select]

#include "stdafx.h"
#include <string.h>
#include <iostream>

using namespace std;

int IO(char* cReturnValue[10]);

int testRoom()
{
    cout << "This is the test room! You find yourself surrounded by gray walls." << endl;
    cout << "There is a single, naked LIGHT bulb on the ceiling, and a CRATE on the floor next to you." << endl;
    cout << endl;
   
    char *cInputTokens[10];
    do
    {
IO(&*cInputTokens);
if (cInputTokens[0] == "get")
           {
               if (cInputTokens[1] == "crate")
                   cout << "The crate is too heavy to lift." << endl;
               else if (cInputTokens[1] == "light")
                   cout << "Ouch! The light bulb is too hot to touch." << endl;
   else
   cout << "I don't recognise that item." << endl;
           };
if (cInputTokens[0] == "die")
{
cout << "You die." << endl;
break;
};
    }while(0 == 0); //Make an exit condition.
return 0;
}
       
int IO(char* cReturnValue[10])
{
    char* cIOline = "\0";
    cin.getline(cIOline, 80);
    int nFinger = 0;
    cReturnValue[nFinger] = strtok(cIOline, "   ,.;:");
    do
    {
        cReturnValue[++nFinger] = strtok(NULL, "  ,.;:");
    }while(nFinger == 8);
return 0;
}

int main()
{
testRoom();
return 0;
}

[ILikePie]

Can you say how reliable argv[0] is? Google seems to think that it can be pretty random, depending on where and how the application was launched.

It isn't really random, it just stores the command you typed into the terminal.

Spoiler (click to show/hide)

Code: [Select]

ron@Tux ~/Media/tmp $ cat argv.c
#include <stdio.h>

int main (int argc, char *argv[])
{
  printf("%s\n", argv[0]);
  return 0;
}

ron@Tux ~/Media/tmp $ gcc -o argv argv.c
ron@Tux ~/Media/tmp $ ./argv
./argv
ron@Tux ~/Media/tmp $ cd
ron@Tux ~ $ Media/tmp/argv
Media/tmp/argv
ron@Tux ~ $ cd /
ron@Tux / $ /home/ron/Media/tmp/argv
/home/ron/Media/tmp/argv
ron@Tux ~ $

Also, if you really want to drop C++, I'd go with Java.

[ILikePie]

Looks like my Bresenham is broken, here it is. It draws only straight lines from x1, y1 to x2 - 1, y2 (or y2 -1). Anyone mind looking at it?

[Shades]

I eliminated the errors and all I get are warnings about strtok being depreciated. But when I run it, immediately after it posts the room description it crashes. What am I doing wrong?

At some point I'll try compiling your code and checking but off the top of my head this is probably the error

Code: [Select]

    char* cIOline = "\0";
    cin.getline(cIOline, 80);
Your reading (upto) 80 characters into a char* which points at a single character space. (And depending on your compiler a constant single character too)

Code: [Select]

char cIOline[80];
memset(&cIOline, 0, 80);
cin.getline(&cIOline, 80);
This might work, for some reason my brain isn't sure if you need the & or not but one of either with or without it will work.

Code: [Select]

std::string cIOline;
cin >> cIOline;
Alternatively this should read the next line of set of characters regardless how long.

Looks like my Bresenham is broken, here it is. It draws only straight lines from x1, y1 to x2 - 1, y2 (or y2 -1). Anyone mind looking at it?

Code: [Select]

for (int x = x1; x < x2; x++)It will never draw to x2 without x <= x2, this will also stop it at y2 -1 with certain deltas.

[ILikePie]

Code: [Select]

for (int x = x1; x < x2; x++)It will never draw to x2 without x <= x2, this will also stop it at y2 -1 with certain deltas.

Aye, that did it, thanks. Now my flood fill is broken (Here). For some reason, it gives a java.lang.StackOverflowError unless I comment out one of the four calls (eg. fill (x - 1, y, Canv, Target, Current) ). Am I missing something?
Also, I really don't want to drop recursion unless it's a must.

[eerr]

so yea, perhaps

char[200] buffer = "\0";
char * = buffer;

would be a good idea

Also strings are supposed to be constant, and therefore you are not supposed to write to them

according to people on the internet,

char *x =string;
x[0]='q';
is liable to give errors/break/not work.

[Supermikhail]

So, I gave a (lame) go to Java yesterday, installed NetBeans. Tutorials above starter confusing. So, my question to ILikePie... or Ron, and anyone else in Java, is it a good idea to try to learn and use java DB thingy for my... well, elements, and eventually chemical compounds, databases? Or maybe it's called CRUD. I'm not sure. And if that converts well to mobile edition.

[lordnincompoop]

ARGLEBARGLEARGLEBARGEARGLEBLARGLEBLARGARGARGARGBLARG

This is really annoying me. It's stopped crashing. but now it won't recognise any of my commands. I'm positive I'm doing something wrong here, but I don't know what.

Wat do?

Code: [Select]

#include "stdafx.h"
#include <string.h>
#include <iostream>

using namespace std;

char* IO();

int testRoom()
{
    cout << "This is the test room! You find yourself surrounded by gray walls." << endl;
    cout << "There is a single, naked LIGHT bulb on the ceiling, and a CRATE on the floor next to you." << endl;
    cout << endl;
   
    char *cInputTokens[10];
    do
    {
cInputTokens[0] = IO();
if (cInputTokens[0] == "get")
{
if (cInputTokens[1] == "crate")
cout << "The crate is too heavy to lift." << endl;
else if (cInputTokens[1] == "light")
cout << "Ouch! The light bulb is too hot to touch." << endl;
else
cout << "I don't recognise that item." << endl;
};
if (cInputTokens[0] == "die")
{
cout << "You die." << endl;
break;
};
    } while(0 == 0); //Make an exit condition.
return 0;
}
       
char* IO()
{
char* cReturnValue[10];
char cIOline[80];
memset(&cIOline, 0, 80);
cin.getline(cIOline, 80);
    int nFinger = 0;
    cReturnValue[nFinger] = strtok(cIOline, "   ,.;:");
    do
    {
        cReturnValue[++nFinger] = strtok(NULL, "  ,.;:");
    } while(nFinger == 8);
return cReturnValue[0];
}


int main()
{
testRoom();
return 0;
}

[Shades]

char[200] buffer = "\0";
char * = buffer;

I'm not even sure that should compile as your making a char[200] equal a const char[1] even if it does only the first character will be \0 which isn't what you want.

Code: [Select]

char[200] buffer;
memset(buffer, 0, sizeof(buffer));

Should do what your trying to achieve.

Also strings are supposed to be constant, and therefore you are not supposed to write to them

const strings are suppose to be constant, as are literal strings (anything in a quotes such as char* literal_string = "hello world"). Any string object that isn't a const, any non const character array or any character pointer to an area of mallocated memory you can write to as you wish.

char *x =string;
x[0]='q';
is liable to give errors/break/not work.

Assuming string is a literal then yes, although with one character it probably wouldn't crash a good compiler should still throw a warning. However if you replaced the char* with std::string it should just work.

[ILikePie]

So, I gave a (lame) go to Java yesterday, installed NetBeans.

I've never used NetBeans, but I'd say the best Java IDE out there is Eclipse. It's got Microsoft-like Intellisense, it puts together Maven packages for you, and it's got a frontend for the Java debugger. It's a bit big, but it's amazing.
I myself use Emacs, but that's because I dislike IDEs, and can work much faster when I have every command mapped to a keystroke.

Tutorials above starter confusing. So, my question to ILikePie... or Ron, and anyone else in Java, is it a good idea to try to learn and use java DB thingy for my... well, elements, and eventually chemical compounds, databases? Or maybe it's called CRUD. I'm not sure. And if that converts well to mobile edition.

Java and C++ are very similar in syntax, start by converting what you have to Java code. I'd just skip the tutorials and go straight to writing. If something doesn't compile, look it up.

[Shades]

So, I gave a (lame) go to Java yesterday, installed NetBeans. Tutorials above starter confusing. So, my question to ILikePie... or Ron, and anyone else in Java, is it a good idea to try to learn and use java DB thingy for my... well, elements, and eventually chemical compounds, databases? Or maybe it's called CRUD. I'm not sure. And if that converts well to mobile edition.

Netbeans and eclipse are both good and have strong Java support.

Using Java db depends mostly on your goals. The strengths of databases are the way you can search, sort and collate the information within them however the data you have may not fix very well onto a relational model. I'd need more information one what your trying to do. However for purely storage then yes I'd suggest using a database, certainly over trying to write your own file format.

For a preference I tend to use sqllite as it's simple local file storage and free to use however the interface for them all is the same through Java so feel free to use Java DB instead, I've not used that one as such so can't really offer a comparison compared to others.

[Supermikhail]

Actually... there's a couple of problems with what I want to do with the database, and one I've just come up with, another I couldn't address in C++. I think I'm going to divide my elements into groups, that is, classes inheriting from a common element class, but I'd like to store their data in one file. Which means that entries might have variable sizes. Or maybe I could fit them all into one class still... I'd sure prefer a premade storage format that the system already knows how to read, because my efforts at teaching it to read a format proposed by me have been unproductive. On C++.

Ideally, I'd like to have the database so that it's editable and accessible for the developer, but the user can't do anything with it (that's why I don't want to do it in text format).