how to access dyn. string-arrays?

Hi,
i have a problem with dynamically allocated strings...
I hope it's ok, if i post this in the C forum though i am using the "new"-keyword (beacuse char* = C-style)
First the code:

Code:

---

char **mult = new char*[20];
for( int i = 0; i < 20; i++ )
    *( mult + i ) = new char[200];

---

This should allocate 20 strings a 200 bytes.
If i try this, for example-

Code:

---

*( *( mult + 1 ) + 5) = 'a';

---

-my program crashes. Strcpy or any other code using this array, crashes, too... How do i access one char or a string from the array not fsckig the program? (please post code)
thanks.

Just got it work with malloc() :)

char **s = ( char** )malloc( 20 );
*( s ) = ( char* )malloc( 200 );
strcpy( s[0], "hello" );
puts( s[0] );

Code:

---

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

int main ( ) {
    int i;
    char **mult;

    // mult[20][200] coming up...
    mult = malloc( 20 * sizeof(char*) );
    for ( i = 0 ; i < 20 ; i++ ) {
        mult[i] = malloc( 200 * sizeof(char) );
    }

    mult[1][5] = 'a';
    return 0;
}

---

> char **s = ( char** )malloc( 20 );
You forgot the *sizeof(char*)

Whilst it's big enough for one pointer, it's not enough for 20

Also, You could have a little fuction do all the ugly work of allocation:

char *NewString(int how_big)
{
char *out = (char *)malloc(sizeof(char) * how_many);
return out;
}


Then of course:

char *input = NewString(100);

...allocates a 100 char string...:)

> char *input = NewString(100);

Is this really any different than:

input = malloc( 100 );

After all, there is no need to typecast the malloc return.

Quzah.

I ran this without crashing.

Code:

---

#include <stdlib.h>
#include <string.h>
#include <iostream.h>
int main(void)
{
char **mult = new char*[20];
for( int i = 0; i < 20; i++ )
    *( mult + i ) = new char[200];

for (i=0; i<20; i++)
  strcpy(mult[i],"My favorite food is pizza!!!");
for (i=0; i<20; i++)
  cout << mult[i] << "..." << endl;

*( *( mult + 1 ) + 5) = 'a';
*( *( mult + 2 ) + 5) = '*';
*( *( mult + 3 ) + 5) = '+';
for (i=0; i<20; i++)
  cout << mult[i] << "..." << endl;

for (i=0; i<20; i++)
  delete []mult[i];
delete []mult;
cout << "Done.\n";
return 0;
}

---

> I ran this without crashing.

Your code is C++, not C.

Quzah.

>Your code is C++, not C.

Did you even read the original post?