Language: C++

#include <iostream>
using namespace std;
  
int main()
{
???int H, W, i, j;
??????while(1){
    cin >> H >> W;
	if ( W == 0 && H == 0) break;
	for (i=0, i<W, i++) {
	???for(j=0, j<H, j++) {
	?????????cout <<'#';
	}
	?????????cout << endl;
	}
	cout << endl
	}
?????????return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:1: error: expected primary-expression before '?' token
    6 | ???int H, W, i, j;
      | ^
a.cc:6:2: error: expected primary-expression before '?' token
    6 | ???int H, W, i, j;
      |  ^
a.cc:6:3: error: expected primary-expression before '?' token
    6 | ???int H, W, i, j;
      |   ^
a.cc:6:4: error: expected primary-expression before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
a.cc:6:4: error: expected ':' before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
      |    :
a.cc:6:4: error: expected primary-expression before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
a.cc:6:4: error: expected ':' before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
      |    :
a.cc:6:4: error: expected primary-expression before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
a.cc:6:4: error: expected ':' before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
      |    :
a.cc:6:4: error: expected primary-expression before 'int'
    6 | ???int H, W, i, j;
      |    ^~~
a.cc:7:1: error: expected primary-expression before '?' token
    7 | ??????while(1){
      | ^
a.cc:7:2: error: expected primary-expression before '?' token
    7 | ??????while(1){
      |  ^
a.cc:7:3: error: expected primary-expression before '?' token
    7 | ??????while(1){
      |   ^
a.cc:7:4: error: expected primary-expression before '?' token
    7 | ??????while(1){
      |    ^
a.cc:7:5: error: expected primary-expression before '?' token
    7 | ??????while(1){
      |     ^
a.cc:7:6: error: expected primary-expression before '?' token
    7 | ??????while(1){
      |      ^
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:7:7: error: expected ':' before 'while'
    7 | ??????while(1){
      |       ^~~~~
      |       :
a.cc:7:7: error: expected primary-expression before 'while'
    7 | ??????while(1){
      |       ^~~~~
a.cc:18:1: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      | ^
a.cc:18:2: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |  ^
a.cc:18:3: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |   ^
a.cc:18:4: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |    ^
a.cc:18:5: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |     ^
a.cc:18:6: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |      ^
a.cc:18:7: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |       ^
a.cc:18:8: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |        ^
a.cc:18:9: error: expected primary-expression before '?' token
   18 | ?????????return 0;
      |         ^
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
a.cc:18:10: error: expected ':' before 'return'
   18 | ?????????return 0;
      |          ^~~~~~
      |          :
a.cc:18:10: error: expected primary-expression before 'return'
   18 | ?????????return 0;
      |          ^~~~~~