Compilare: user.cpp: In function ‘int acoper()’: user.cpp:12:8: warning: unused variable ‘ok’ [-Wunused-variable] {int i,ok,j; ^ user.cpp: In function ‘int valid(int)’: user.cpp:23:6: warning: unused variable ‘i’ [-Wunused-variable] {int i; ^ user.cpp: In function ‘void back(int)’: user.cpp:41:5: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (valid(k)) if(sol(k)) tip(k); ^