why don't my pointers work? - c

Question

I am trying to write the old painter game, where you paint around squares and when the perimeter is done the square changes colour, using ncurses. I have written a simple level editor that lets me draw the squares using an asterisk. I have a block structure and an array of them and can create the blocks by brute-force scanning the screen for asterisks and setting blocks to those locations. So I realised that each block is joined to 2 - 4 other blocks, so I could just have pointers to next up/dn/lt/rt blocks and follow the pointers. This would save time because I wouldn't have to check for boundary conditions or that the player stayed on the line, i could simply check if the ptr was null and if so not let the player move in that direction. So I can save the block array and load it into the painter game and it displays it all correctly. I have a ptr to the current block cur_blk which I have set to point to array element 5, and this works. If I gdb, I can print out the value of *cur_blk and it shows everthing is right, but the pointers don't work. I think the problem is in the level editor, but I am stuck.
Here is some code. This is the block struct:
struct block{
int id;
int row, col;
int alive;
struct block *next_up, *next_dn, *next_lt, *next_rt;
struct square *my_squares;
};
Here is the block array setup:
struct block *bp;
int cnt = 0;
for(bp = &the_blocks[0]; bp < &the_blocks[1024]; bp++){
bp->id = cnt;
bp->row = 0;
bp->col = 0;
bp->alive = FALSE;
bp->next_up = NULL;
bp->next_dn = NULL;
bp->next_lt = NULL;
bp->next_rt = NULL;
bp->my_squares = (struct square *)malloc(sizeof(struct square)*4);
cnt++;
}
here is the code to give the blocks the correct co-ords, and link them together - the linky code is in the for(d=0;d<blk_cnt;d++) loop. It rescans the array comparing co-ords, such that if the row is one less and the col is the same then that is set to the_blocks[c].next_up. I am pretty sure this is where the error is but I don't know what it is.
char cc, dn_ch, rt_ch; // cur/next chars
int row, col;
//create blocks
for(row=0;row<24;row++){
for(col=0;col<61;col++){
cc = mvinch(row,col);
if(cc == '*'){
the_blocks[blk_cnt].row = row;
the_blocks[blk_cnt].col = col;
the_blocks[blk_cnt].alive = TRUE;
blk_cnt++;
}
if(row<24) ;
dn_ch = mvinch(row+1, col);
if(col<60) ;
rt_ch = mvinch(row,col+1);
if(cc == '*' && dn_ch == '*' && rt_ch == '*')
make_square(row,col);
}
}
//make into squares and link blocks
int c,d,e, scnt;
for(c=0;c<blk_cnt;c++){
int row = the_blocks[c].row;
int col = the_blocks[c].col;
for(e=0;e<sq_cnt;e++){
// for each square, check top/base then left side and rigth side.
// use tlx, tly etc
scnt = 0;
int tlx = the_squares[e].tlx;
int tly = the_squares[e].tly;
int blx = the_squares[e].blx;
int bly = the_squares[e].bly;
int trx = the_squares[e].trx;
int try = the_squares[e].try;
int brx = the_squares[e].brx;
int bry = the_squares[e].bry;
if(row == tly && col >=tlx && col <= trx){
the_blocks[c].my_squares[scnt] = the_squares[e];
scnt++;
}
if(row == bly && col >=blx && col <= brx){
the_blocks[c].my_squares[scnt] = the_squares[e];
scnt++;
}
if(col == tlx && row >=tly && row <= bly){
the_blocks[c].my_squares[scnt] = the_squares[e];
scnt++;
}
if(col == trx && row >=try && row <= bry){
the_blocks[c].my_squares[scnt] = the_squares[e];
scnt++;
}
}
for(d=0;d<blk_cnt;d++){
if((the_blocks[d].row == row-1) && (the_blocks[d].col == col)){
//the_blocks[c].next_up = (struct block *)malloc(sizeof(struct block));
the_blocks[c].next_up = &the_blocks[d];
}
if((the_blocks[d].row == row+1) && (the_blocks[d].col == col)){
//the_blocks[c].next_dn = (struct block *)malloc(sizeof(struct block));
the_blocks[c].next_dn = &the_blocks[d];
}
if(( the_blocks[d].col == col-1) && (the_blocks[d].row == row)){
//the_blocks[c].next_lt = (struct block )malloc(sizeof(struct block));
the_blocks[c].next_lt = &the_blocks[d];
}
if((the_blocks[d].col == col+1) && (the_blocks[d].row == row)){
//the_blocks[c].next_rt = (struct block *)malloc(sizeof(struct block));
the_blocks[c].next_rt = &the_blocks[d];
}
}
}
Here is the code from the painter game that sets the cur_blk pointer
cur_blk = &the_blocks[5];
move(cur_blk->row, cur_blk->col);
addch('#');
refresh();
and this is the move code, where I thought I could just follow the pointers:
switch(dir){
case UP : if(cur_blk->next_up != NULL){
cur_blk = cur_blk->next_up;
moved = TRUE;
break;
}
case DOWN : if(cur_blk->next_dn != NULL){
cur_blk = cur_blk->next_dn;
moved = TRUE;
break;
}
case LEFT : if(cur_blk->next_lt != NULL){
cur_blk = cur_blk->next_lt;
moved = TRUE;
break;
}
case RIGHT : if(cur_blk->next_rt != NULL){
cur_blk = cur_blk->next_rt;
moved = TRUE;
break;
}
}
I am so stuck it is unreal. Thanks in advance for any help. I can post more code if needed. The level editor works apart from the linky bit!