int xsize = 5;
int ysize = 5;
MapTile Map[xsize][ysize];
A Simple Newbie C Question that I should know...
Author
Grr, this always annoys me. Why can''t I do this, and what''s the best way to get around it?
MapTile* Map = (MapTile*) malloc(xsize*ysize*sizeof(MapTile));
Map[x][y] becomes Map[x*ysize+y]
When you''re done with the map, do not forget to do free(Map);
Map[x][y] becomes Map[x*ysize+y]
When you''re done with the map, do not forget to do free(Map);
Author
Thanks Fruny.
I know I said C, but I''m actually writing this in C++.
How would I format that using new and delete?
I did it like this, just want to make sure that''s correct.
I know I said C, but I''m actually writing this in C++.
How would I format that using new and delete?
I did it like this, just want to make sure that''s correct.
CMapTile* Map = new CMapTile[xsize*ysize];
Yes that''s correct. Remember to use delete[] instead of delete to deallocate the arrays memory.
If you''re wondering why your original way didn''t work it''s because you try to create an array using variables to give the size. These variables can change at run time and when you do something like MapTile Map[2][2] in C++ it is allocated statically. That is the size of the array is hardcoded into the program and cannot be altered hence the values you give as the array sizes have to be constant(the way the memory is allocated to dynamic allocation will also differ, but I won''t get into that). If you put const in front of your two variable definitions, it should work. Though I believe you are trying to acomplish dynamic allocation (i.e. you can have different sizes depending on the size of the map) so Fruny''s way will work fine.
If you''re wondering why your original way didn''t work it''s because you try to create an array using variables to give the size. These variables can change at run time and when you do something like MapTile Map[2][2] in C++ it is allocated statically. That is the size of the array is hardcoded into the program and cannot be altered hence the values you give as the array sizes have to be constant(the way the memory is allocated to dynamic allocation will also differ, but I won''t get into that). If you put const in front of your two variable definitions, it should work. Though I believe you are trying to acomplish dynamic allocation (i.e. you can have different sizes depending on the size of the map) so Fruny''s way will work fine.
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