Compilare: main.cpp: In function 'void f(int, int)': main.cpp:27:22: warning: NULL used in arithmetic [-Wpointer-arith] 27 | if ( q[l-1][c] !=NULL && q[l-1][c] !='#' ) | ^~~~ main.cpp:29:22: warning: NULL used in arithmetic [-Wpointer-arith] 29 | if ( q[l+1][c] !=NULL && q[l+1][c] !='#' ) | ^~~~ main.cpp:31:22: warning: NULL used in arithmetic [-Wpointer-arith] 31 | if ( q[l][c-1] !=NULL && q[l][c-1] !='#' ) | ^~~~ main.cpp:33:22: warning: NULL used in arithmetic [-Wpointer-arith] 33 | if ( q[l][c+1] !=NULL && q[l][c+1] !='#' ) | ^~~~