Thread: 2d arrays

In addition, this *might* help

#define MAXCHARS 80 /* the chars per line */
#define MAXROWS 3 /* the index elements 0-2*/

fgets(chArr[index], MAXCHARS, stdin);

don't forget to strip out the '\n' when using fgets

length = strlen(chArr[index])-1;
chArr[index][length] = '\0';

or use strcpy

strcpy(chArr[index], "some string");

>how do i delcare a 2 dimensional string array????
Maybe I'm just reading this wrong, but if a string is an array of char that is terminated by a null character '\0', then wouldn't a two-dimensional array of strings would be a three-dimensional array of char?

Code:

#include <stdio.h>

#define ROWS    2
#define COLS    4
#define LENGTH 50

/* one way */
char a [ LENGTH ];
char b [ COLS ] [ LENGTH ];
char c [ ROWS ] [ COLS ] [ LENGTH ];

/* another way */
char d [ ] = "text";
char e [ ] [ LENGTH ] =
{
    "an", "array", "of", "text",
};
char f [ ] [ COLS ] [ LENGTH ] =
{
    { "First",  "array", "of", "text" },
    { "Second", "array", "of", "text" },
};

/* yet another way */
char g [ LENGTH ] = "text";
char h [ COLS ] [ LENGTH ] =
{
    "an", "array", "of", "text",
};
char i [ ROWS ] [ COLS ] [ LENGTH ] =
{
    { "First",  "array", "of", "text" },
    { "Second", "array", "of", "text" },
};

#define ARRAYSIZE(x)    (sizeof(x)/sizeof(*(x)))

int main(void)
{
    int j,k;
    for(j = 0; j < ARRAYSIZE(i); ++j)
    {
        for(k = 0; k < ARRAYSIZE(*i); ++k)
        {
            printf("i[%d][%d] = \"%s\"\n", j, k, i [ j ] [ k ]);
        }
    }
    return 0;
}

/* my output
i[0][0] = "First"
i[0][1] = "array"
i[0][2] = "of"
i[0][3] = "text"
i[1][0] = "Second"
i[1][1] = "array"
i[1][2] = "of"
i[1][3] = "text"
*/

When I first read "array of strings" I was thinking of the string class in c++, but this is the c board... perhaps your response is what TOP wanted to know???

Originally posted by Vber
To be more exactly, a simple example:

Code:

const char sStrs[50][50] = {
    "Hello there, string 1",
    "Wtf, string 2 here?",
    "Multidemensional array, doh",
    "I love this sould",
    "C/C++ r0x",
};

Hmmm. I see a two-dimensional array of chars; a one-dimensional array of strings.

Code:

#include <stdio.h>
int main(void)
{
   int i;
   for ( i = 0; i < 5; ++i )
   {
      puts(sStrs[i] /* where's the other dimension? */ );
   }
   return 0;
}

It is almost a declaration of an array of 50 arrays of 50 const chars.

[edit]
It could be used as an array of 50 read-only strings that are at most 50 characters in length.
[/edit]

Code:

char sStrs[50][50];

>Dave isn't this a multi-dimensional array?

Of characters, yes; of strings, no. Remember the original question was...

>how do i delcare a 2 dimensional string array????


All righty, one last try. Let's start with ints.

Code:

int x; /* a single int, not an array */
int one[10]; /* one-dimensional array */
int two[3][4]; /* two-dimensional array */

Okay now let's take a look at a string.

Code:

char text[20]; /* a single string (or an array of 20 characters) */

See how x differs from text? To be a string, you already need to be an array of char (and end with a '\0').

So in order to be an array of strings, we have to add a second dimension.

Code:

char one[4][20]; /* array of 4 strings (or a 4x20 array of characters) */

Then we would need to have a three-dimesional char array in order to have a two-dimensional (the first multi-dimensional) array of strings.

Code:

char two[2][4][20]; /* a 2x4 array of strings (or a 2x4x20 array of characters) */

Would a typedef help?

Code:

typedef char str[20];

str one[5] = /* array of 5 strings (up to 20 characters each) */
{ "one", "two", "three", "four", "five" };

str two[2][4] = /* 2x4 array of strings (up to 20 characters each) */
{
   { "one", "two", "three", "four" },
   { "five", "six", "seven", "eight" },
};

But then again, maybe the one-dimensional array of strings is what cnewbee wanted all along.