OH, Pascal !

[i586coder]

Hi folks,

I have trouble with this pascal chunk.
How I can convert this chunk to C code

Code: Select all

type
 points:=array[1..10] of integer

 procedure fill_area_solid(count: integer; x,y:points);
  type
   each_entry:=record
   y_top:integer;
   x_int:real;
   delta_y:integer;
  x_change_per_scan:real
  end;
  list=array[0..10]   of each_entry;
  var
    slides:list
    side_count,first_s,last_s,scan,bottomscan,x_int_count,r :integer;

begin
 {any code whatever}
end.

note:
i copied this code as is from source,& my knowledge of pascal is so faaar

[Velko]

Translated almost literally:

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struct each_entry {
    int y_top;
    float x_int;
    int delta_y;
    float x_change_per_scan;
};

typedef int points[10];
typedef struct each_entry list[11];

void fill_area_solid(int count, points x, points y)
{
    list slides;
    int side_count,first_s,last_s,scan,bottomscan,x_int_count,r;
    /* any code whatever */
}

Note about points: in Pascal it's 1-based array. In this C code 0-based, of course. And yes, arrays are passed by value .

[i586coder]

Thanks, it seems work

[Velko]

Well, of course that code needs a little optimization. Passing two 40-byte variables by value is not a very good idea. They should be passed by reference/pointer.

In Pascal that should be:

Code: Select all

procedure fill_area_solid(count: integer; const x,y:points);

In C:

Code: Select all

void fill_area_solid(int count, int *x, int *y)

Even better would be to use array of struct point instead of 2 seperate arrays

[pcmattman]

And yes, arrays are passed by value

Huh? Structs are passed by value (unless explicitly passed by reference, which IIRC you can't do in C - so you pass as a pointer). Arrays in C are effectively pointers, and as such passing an array is passing an address.

[Velko]

With,

Code: Select all

typedef int points[10];

you get a type points and sizeof(points)==40.

Then you declare a function

Code: Select all

void fill_area_solid(int count, points x, points y)

which expects parameters x and y to be that 40-byte chunk. Or am I wrong?

I'm not saying thats good, but thats exactly what Pascal code was doing.

[pcmattman]

That may be what the Pascal code was doing. but I was talking about C in response to this:

In this C code 0-based, of course. And yes, arrays are passed by value