The board is represented as a one-dimensional array.
Neighbors of a point can be computed with offsets WE and NS, so that the four neighbors of point p are:
p + SG_NS
p - SG_WE p p + SG_WE
p - SG_NS
The board is surrounded by one line of border points (if size is SG_MAX_SIZE) in all directions; also diagonally out from the corners.
SgPointUtil::Pt, SgPointUtil::Row, and SgPointUtil::Col can be used to convert between points and coordinates. The coordinates start with 1 and the conversion is independent of the board size. Pt(1, 1), which corresponds to A1, is the lower left corner of the board.
The following point numbers are valid, if the code was compiled with SG_MAX_SIZE = 19 (which is used in the default version of SgPoint.h).
19|381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 18|361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 17|341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 16|321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 15|301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 14|281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 13|261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 12|241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 11|221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 10|201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 9|181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 8|161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 7|141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 6|121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 5|101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 4| 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 3| 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 2| 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1| 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 [A] [B] [C] [D] [E] [F] [G] [H] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T]