Simple question with array of strings

**Tim Love** · Jul 22 '05, 09:23 PM

Re: Simple question with array of strings

rafi.kfir@telra d.co.il (Rafi Kfir) writes:
[color=blue]
>Hi,[/color]
[color=blue]
>This may look as a smiple task to most of you, but to me (a beginner
>with C), it drives me crazy.[/color]
[color=blue]
>All I want is that one function passes a two dimensional array of
>strings to another function.
> ...[/color]
[color=blue]
>I would be happy to be advised of the best way to do it.[/color]
Look up <vector> and <string> in a C++ book - or online.

**Victor Bazarov** · Jul 22 '05, 09:23 PM

Re: Simple question with array of strings

Rafi Kfir wrote:[color=blue]
> This may look as a smiple task to most of you, but to me (a beginner
> with C), it drives me crazy.[/color]

If you need help with C, you should consider comp.lang.c as your NG of
choice.
[color=blue]
> All I want is that one function passes a two dimensional array of
> strings to another function.
>
> example:
> NOTE: the strings can be of different length and the array will be
> initialized many times to differnt values.
>
> void fun_1()
> {
> char **Arr[3][2]= {'\0'}; //I want to define a 3x2 array of strings
> of
> //different length (max 32 ch)[/color]

In C++ one should always consider standard containers for that:

vector<vector<s tring> > Arr;

In C you probably will want to declare an array of pointers to char:

char *Arr[3][2] = { 0 };

and then somehow allocate the memory. Although, I'd susupect that to
have an array of 33-char arrays would be easier (since you limited your
strings to 32 bytes):

char Arr[3][2][33];
[color=blue]
> //Arr initialization
> // Arr ["ONE", "1"]
> // ["Two", "2"]
> // ["THREE", "3"][/color]

If you declare your array as 3-dimensional, you still should be able to
initialise it as

char Arr[3][2][33] =
{ { "ONE", "1" }, { "Two", "2" }, { "Three", "3" } };
[color=blue]
>
> fun2(Arr);
> }
>
> void fun_2(char **rcvArr)[/color]

Just repeat the declaration of the Arr in your function declaration (but
pick the right name for it first, 'fun2' or 'fun_2'):

void funX(char Arr[3][2][33])
[color=blue]
> {
>
> }
>
> CAn anybody help me with how to define it, how to initialize it and
> hwo to send and receive it as a parameter.[/color]

How about a book on C? Do you have any?
[color=blue]
> I suspect that I must define some buffer length. The question is
> should I select fixed length (e.g. 32 ch per string) or a veriable
> length. In the other option I would probably need to use malloc in
> order to allocate memory...[/color]

Right.
[color=blue]
> I would be happy to be advised of the best way to do it.[/color]

There is no "best" way to skin the proverbial cat. There is always more
than one way and each has its advantages and drawbacks.
[color=blue]
> Also, when I
> initialize the array, I preffer that it will take as little text space
> as possible (for example, the best will be to define it all in one
> line!).[/color]

Yes, you could do that too if your array doesn't change. But it's usually
a maintenance nightmare.

const char arr_[] = "ONE\01\0Two\02 \0THREE\03\0";
/* ^0 ^4 ^6 ^10^12 ^18
const char* const Arr[3][2] =
{{ arr_, arr_+ 4 }, { arr_+ 6, arr_+ 10 }, { arr_+12, arr_+18 }};

V

**John Harrison** · Jul 22 '05, 09:23 PM

Re: Simple question with array of strings

"Rafi Kfir" <rafi.kfir@telr ad.co.il> wrote in message
news:f74d6851.0 411020835.2a09c 462@posting.goo gle.com...[color=blue]
> Hi,
>
> This may look as a smiple task to most of you, but to me (a beginner
> with C), it drives me crazy.[/color]

news:comp.lang. c if you really are interested in C and not C++.
[color=blue]
>
> All I want is that one function passes a two dimensional array of
> strings to another function.[/color]

It's impossible to pass arrays in C or C++. You have to use pointers
instead. This is one reason (among many) to use vectors instead of arrays in
C++.
[color=blue]
>
> example:
> NOTE: the strings can be of different length and the array will be
> initialized many times to differnt values.
>
> void fun_1()
> {
> char **Arr[3][2]= {'\0'}; //I want to define a 3x2 array of strings[/color]

char* Arr[3][2] = { { "ONE", "1" }, { "TWO", "2" }, { "THREE", "3" } };
[color=blue]
> of
> //different length (max 32 ch)
> //Arr initialization
> // Arr ["ONE", "1"]
> // ["Two", "2"]
> // ["THREE", "3"]
>
> fun2(Arr);
> }
>
> void fun_2(char **rcvArr)[/color]

void fun_2(char* (*rcvArr)[2])

Horrible.
[color=blue]
> {
>
> }
>
> CAn anybody help me with how to define it, how to initialize it and
> hwo to send and receive it as a parameter.
>
> I suspect that I must define some buffer length. The question is
> should I select fixed length (e.g. 32 ch per string) or a veriable
> length. In the other option I would probably need to use malloc in
> order to allocate memory...[/color]

Yes, you are right.
[color=blue]
>
> I would be happy to be advised of the best way to do it. Also, when I
> initialize the array, I preffer that it will take as little text space
> as possible (for example, the best will be to define it all in one
> line!).[/color]

Decide what you are programming, C or C++. Post to the appropriate
newsgroup.

If you are programming C then you have to do something like the rubbish
above.

If you are programming C++, then you can use vector and string and forget
about the rubbish above.

#include <vector>
#include <string>
using namespace std;

struct StringPair
{
StringPair(stri ng f, string s)
{
first = f;
second = s;
}
string first;
string second;
};

typedef vector<StringPa ir> StringArray;

void fun_2(StringArr ay& Arr)
{
// do something with Arr
}

int main()
{
StringArray Arr;
Arr.push_back(S tringPair("ONE" , "1"));
Arr.push_back(S tringPair("TWO" , "2"));
Arr.push_back(S tringPair("THRE E", "3"));
}

Now don't you think that a bit easier. Everything is dynamic, everything
gets freed automatically.

john

**sirclif** · Jul 22 '05, 09:24 PM

Re: Simple question with array of strings

#include <stdlib.h>
#include <stdio.h>

void print(char *arg[])
{
int i,j;
for( i = 0; i < 3; i++)
{
for( j = 0; j < 4; j++)
{
printf("%c",arg[i][j]);
}
printf("\n");
}
}

int main()
{
char **ch;
int i,j;

ch = (char**)calloc( 3,sizeof(char*) );
for(i = 0; i < 3; i++)
{
ch[i] = (char *)calloc(4,size of(char));
}
for(i = 0; i < 3; i++)
{
for(j = 0; j < 4; j++)
{
ch[i][j] = 'c';
}
}
print(ch);

return 0;
}

**sirclif** · Jul 22 '05, 09:24 PM

Re: Simple question with array of strings

#include <stdlib.h>
#include <stdio.h>

void print(char *arg[])
{
int i,j;
for( i = 0; i < 3; i++)
{
for( j = 0; j < 4; j++)
{
printf("%c",arg[i][j]);
}
printf("\n");
}
}

int main()
{
char **ch;
int i,j;

ch = (char**)calloc( 3,sizeof(char*) );
for(i = 0; i < 3; i++)
{
ch[i] = (char *)calloc(4,size of(char));
}
for(i = 0; i < 3; i++)
{
for(j = 0; j < 4; j++)
{
ch[i][j] = 'c';
}
}
print(ch);

return 0;
}

**sirclif** · Jul 22 '05, 09:24 PM

Re: Simple question with array of strings

#include <stdlib.h>
#include <stdio.h>

void print(char *arg[])
{
int i,j;
for( i = 0; i < 3; i++)
{
for( j = 0; j < 4; j++)
{
printf("%c",arg[i][j]);
}
printf("\n");
}
}

int main()
{
char **ch;
int i,j;

ch = (char**)calloc( 3,sizeof(char*) );
for(i = 0; i < 3; i++)
{
ch[i] = (char *)calloc(4,size of(char));
}
for(i = 0; i < 3; i++)
{
for(j = 0; j < 4; j++)
{
ch[i][j] = 'c';
}
}
print(ch);

return 0;
}

**sirclif** · Jul 22 '05, 09:24 PM

Re: Simple question with array of strings

oops, guess i should have read the bright red instruction at the top of the
page telling me not to resubmit if my reply doent show up right away. sorry
about that

**Jon Bell** · Jul 22 '05, 09:24 PM

Re: Simple question with array of strings

In article <f74d6851.04110 20835.2a09c462@ posting.google. com>,
Rafi Kfir <rafi.kfir@telr ad.co.il> wrote:[color=blue]
>
>This may look as a smiple task to most of you, but to me (a beginner
>with C), it drives me crazy.
>
>All I want is that one function passes a two dimensional array of
>strings to another function.[/color]

Doing this using old-style arrays and char* "strings" is *not* a simple
task, even for experienced programmers. C++ has tools that make it much
easier, namely the standard 'vector' and 'string' data types.
[color=blue]
>example:
>NOTE: the strings can be of different length and the array will be
>initialized many times to differnt values.[/color]

No problem. The standard 'string' type automatically resizes itself
appropriately.

#include <vector>
#include <string>

using namespace std;
[color=blue]
>void fun_1()
>{
> char **Arr[3][2]= {'\0'}; //I want to define a 3x2 array of strings
>of
> //different length (max 32 ch)
> //Arr initialization
> // Arr ["ONE", "1"]
> // ["Two", "2"]
> // ["THREE", "3"][/color]

vector<vector<s tring> > Arr (3, vector<string>( 2));
Arr[0][0] = "ONE";
Arr[0][1] = "1";
// etc. for the other elements
[color=blue]
>
> fun2(Arr);
>}
>
>void fun_2(char **rcvArr)[/color]

void fun_2 (vector<vector< string> >& rcvArr)
// and make it const if you don't plan to modify the data inside the
// function[color=blue]
>{
>
>}[/color]

--
Jon Bell <jtbellm4h@pres by.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA

**JKop** · Jul 22 '05, 09:25 PM

Re: Simple question with array of strings

void Func(char**);
//I don't work with pointers to pointers much
//so I'd have to look-up the correct way to make
//the above argument const-correct.

int main()
{
char* string_array[3][2];

string_array[0][0] = "One";
string_array[0][1] = "1";
string_array[1][0] = "Two";
string_array[1][1] = "2";
string_array[2][0] = "Three";
string_array[2][1] = "3";

Func(string_arr ay);
}

void Func(char** string_array);
{

}

-JKop

Simple question with array of strings

Simple question with array of strings

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