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Getting Array error

Crazy1596 (12)
I have been working on a code for a week now and keep getting the same error everytime. The code is supposed to move an ASCII smiley face up,down,left,and right but the error I keep getting is preventing me from moving on.
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#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
    char b[25][25];
    int pos=12;
    system("color E1");

for(int row=0; row<25; row++)
    {
        for(int col=0; col<25; col++)
        {
            b[row][col]=' ';
        }
    }
    for(int col=0; col<25; col++)
    {
        b[0][col]=219;
        b[23][col]=219;
    }
    for(int row=0; row<25; row++)
    {
        b[row][0]=219;
        b[row][23]=219;
    }

    for(int r=0; r<25; r++)
    {
        b[r]=' ';
    }
    b[pos]='\1';


while(true)
{
    system("cls");

    if(GetAsyncKeyState(VK_RIGHT)&& pos<24)
    {
        b[pos]=' ';
        b[++pos]='\1';
    }
    if(GetAsyncKeyState(VK_LEFT)&& pos>1)
    {
        b[pos]=' ';
        b[--pos]='\1';
    }

    cout<<endl<<endl;
    for(int j=0; j<50; j++)
    {
        cout<<b[j];
    }
}
      return 0;
}

On line 31 it gives the error: incompatible types in assignment of 'char' to 'char [25]'|
[/code]
Any help that can be given would be most appreciated.
Thank you, Crazy1596
yelnatz (100)
It's because b[r] is a pointer to the r'th char array ( It's a 2D matrix right?).
Crazy1596 (12)
Yes, it is a 2d matrix it is supposed to print out a 25x25 border that the smiley face stays inside.
yelnatz (100)
You can't set b[r] to ' ' since I told you, b[r] is a pointer to a char array.

b[r] -> b[r][1], b[r][2], b[r][3], b[r][4], b[r][5], b[r][6]... etc.

What are you trying to do in that for loop anyway? set the r'th row into blank?
Last edited on
Crazy1596 (12)
So i have to call out every part of the array like that? b[r][1]-b[r][25]? and it should stop giving me the error?
yelnatz (100)
It should, try it out.
Crazy1596 (12)
I tried it and now it looks like this:
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#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
    char b[25][25];
    int pos=12;
    system("color E1");

for(int row=0; row<25; row++)
    {
        for(int col=0; col<25; col++)
        {
            b[row][col]=' ';
        }
    }
    for(int col=0; col<25; col++)
    {
        b[0][col]=219;
        b[23][col]=219;
    }
    for(int row=0; row<25; row++)
    {
        b[row][0]=219;
        b[row][23]=219;
    }

    for(int r=0; r<25; r++)
    {
        b[r][1],b[r][2],b[r][3],b[r][4],b[r][5],b[r][6],b[r][7],b[r][8],b[r][9],b[r][10],b[r][11],b[r][12],b[r][13],b[r][14],b[r][15],b[r][16],b[r][17],b[r][18],b[r][19],b[r][20],b[r][21],b[r][22],b[r][23],b[r][24],b[r][25],=' ';
    }
    b[pos]='\1';


while(true)
{
    system("cls");

    if(GetAsyncKeyState(VK_RIGHT)&& pos<24)
    {
        b[pos]=' ';
        b[++pos]='\1';
    }
    if(GetAsyncKeyState(VK_LEFT)&& pos>1)
    {
        b[pos]=' ';
        b[--pos]='\1';
    }

    cout<<endl<<endl;
    for(int j=0; j<50; j++)
    {
        cout<<b[j];
    }
}
      return 0;
}

But i get more errors now:
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||=== HWW#, Debug ===|
E:\college code\HWW#\main.cpp||In function 'int main()':|
E:\college code\HWW#\main.cpp|31|warning: left operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|warning: right operand of comma operator has no effect [-Wunused-value]|
E:\college code\HWW#\main.cpp|31|error: expected primary-expression before '=' token|
E:\college code\HWW#\main.cpp|33|error: incompatible types in assignment of 'char' to 'char [25]'|
E:\college code\HWW#\main.cpp|42|error: incompatible types in assignment of 'char' to 'char [25]'|
E:\college code\HWW#\main.cpp|43|error: incompatible types in assignment of 'char' to 'char [25]'|
E:\college code\HWW#\main.cpp|47|error: incompatible types in assignment of 'char' to 'char [25]'|
E:\college code\HWW#\main.cpp|48|error: incompatible types in assignment of 'char' to 'char [25]'|
||=== Build finished: 6 errors, 24 warnings (0 minutes, 2 seconds) ===|
yelnatz (100)
Wait, haha. You literally put in what I wrote as a guide of what's happening.


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for(int x=0; x<25; x++){
 for(int y=0; y<25; y++){
  b[x][y] = ' ';
 }
}


This will set all the stuff in b to ' '. Not sure if that was the main goal of your for for loop though.
Last edited on
Crazy1596 (12)
Great that one works now. But I still get more of the incompatible types char to char [25] on lines: 44,45,49,and 50. b[x][y] wont work in that spot. What will?
yelnatz (100)
You really can't access a 2D matrix like it's a 1D array. ( well you can, but errors )

Crazy1596 (12)
How do i fix the errors then?
yelnatz (100)
Hmm, since b is 25x25 you get this

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 0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24 
 25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49 
 50  51  52  53  54  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74 
 75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99 
100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 
125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 
150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 
175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 
200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 
300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 
325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 
350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 
375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 
400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 
425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 
450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 
475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 
500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 
525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 
550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624


So to access the 27th element that's the row = 1, column = 2.

General formula for that I think is 

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x = position / 25 ; 
y = position % 25;


Then the 27th element is b[1][2]
Crazy1596 (12)
The whole point of this code is to make a blank square 25x25 with a border around it that a smiley face can move up down left and right inside of.
yelnatz (100)
Based on the table I gave you, what is 'pos' ?
Crazy1596 (12)
Pos is just the starting point of the face. It can be changed to any spot on the table.
yelnatz (100)
Ok, progress.

So that's what pos means?

When you do 'b[pos]', when pos is 0, it means this thing: 

 
 
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So it's getting confused when you say b[pos] = ' '; since you know, there's a lot of them...

EDIT: b[pos] is the row, not column.
Last edited on
Crazy1596 (12)
So how do i you know not make it a lot of them? include both an x and y? like b[1][2]?
yelnatz (100)
Since like I assume you're making the smiley face go left or right, then its x value the one that's changing and the y value is constant( it's not going up or down ). You know, like in the cartesian plane in maths.

Then go something like:

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y = get the smileys y position
if(GetAsyncKeyState(VK_RIGHT)&& x<24)
{
 b[x][y]=' ';
 b[++x][y]='\1';
}


So y didn't change but x did.
Last edited on
Crazy1596 (12)
Right now the code only has the left and right but I will be adding the up and down once these errors get fixed.
yelnatz (100)
I already told you how to get x and y above.

And of course 

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cout<<endl<<endl;
for(int j=0; j<50; j++)
{
   cout<<b[j];
}


Won't work as we've discussed. (And there's 25x25 = 625 elements in b, not 50 )
Last edited on
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