Passing multidimensional arrays...

[sunaj]

Hi,

I've got this function (I didn't write it):
void polyinterp2(float x1a[], float x2a[], float **ya, int m, int n, float x1,
float x2, float *y, float *dy)
and I know that I'm supposed to supply a [1..n][1..m] array to the variable ya.
How do I do that? I don't know what ** means...
If you can, please give an example where I can see the declarations and the function call. I'll be greatfull and you'll get a star if it works
Sunaj
'The gap between theory and practice is not as wide in theory as it is in practice'

 

[sunaj]

Hi again,

Now I got this far:
--------------------------------------------------
//Declaring and initializing other variables
float** y;
y=new float*[n+1];
for(int i=1;i<n+2;i++)
y=new float[n+1];

//here I want to insert values into the 2D array, how?

polyinterp2(x1,x1,y,5,5,1.5,1.5,&ny,&ndy)
---------------------------------------------------

Anyone....?? Sunaj
'The gap between theory and practice is not as wide in theory as it is in practice'

 

[sunaj]

Why is it that the simplest things sometimes can cause a lot of grey hair?
It works like a charm now.. Sunaj
'The gap between theory and practice is not as wide in theory as it is in practice'

 

[Leibnitz]

Here is a little program that i have wrote for helping:

#include <iostream.h>
#include <stdlib.h>
typedef int Array[100];
void main()
{
Array *y; // create the array (25 by 100)
y = new Array[25]; // allocating memory to it
if( y == NULL ) // test if memory have been allocated
exit(1);

for( int i = 0; i < 25; i++ ) // input the array
{
for( int j = 0; j < 100; j++ )
y[j] = 8;
}

for( i = 0; i < 25; i++ ) // output the array
{
for( int k = 0; k < 100; k++ )
cout<<&quot;[&quot;<<i<<&quot;]&quot;<<&quot;[&quot;<<k<<&quot;] = &quot;<<y[k]<<endl;
}
delete [] y; // freeing the memory that has been allocated to the array
}

 

[Leibnitz]

Now for returning a 2D array,you can use this:

#include <iostream.h>
#include <stdlib.h>
typedef float Array[100];
Array *Function( int size )
{
Array *y; // create the array
y = new Array[size];// allocating memory to it ('size' by 100)

if( y == NULL ) // test if memory have been allocated
exit(1);

for( int i = 0; i < 25; i++ ) // input the array
{
for( int j = 0; j < 100; j++ )
y[j] = 1.568f;
}
return y;
}

void main()
{
Array *values;
values = Function(25);

for( int m = 0; m < 25; m++ ) // output the array
{
for( int k = 0; k < 100; k++ )
cout<<&quot;[&quot;<<m<<&quot;]&quot;<<&quot;[&quot;<<k<<&quot;] = &quot;<<values[m][k]<<endl;
}
delete [] values; // freeing the memory that has been allocated to the array
}

 

[Leibnitz]

By the way the &quot;**&quot; in &quot;**ya&quot; means that the variable &quot;ya&quot; is a pointer of pointer ( a pointer that holds the address of another one ).
In this example &quot;ya&quot; will hold the address of the pointer &quot;*ya&quot; i think.