Compilare: user.cpp: In function ‘bool Check(int)’: user.cpp:41:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(( vis[i].first <= v[nr].x && v[nr].y >= vis[i].first ) || ( v[nr].y <= vis[i].second && v[nr].x >=vis[i].first ) ) ^ user.cpp:41:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(( vis[i].first <= v[nr].x && v[nr].y >= vis[i].first ) || ( v[nr].y <= vis[i].second && v[nr].x >=vis[i].first ) ) ^ user.cpp:41:84: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(( vis[i].first <= v[nr].x && v[nr].y >= vis[i].first ) || ( v[nr].y <= vis[i].second && v[nr].x >=vis[i].first ) ) ^ user.cpp:41:111: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(( vis[i].first <= v[nr].x && v[nr].y >= vis[i].first ) || ( v[nr].y <= vis[i].second && v[nr].x >=vis[i].first ) ) ^ user.cpp: In function ‘int main()’: user.cpp:53:6: warning: unused variable ‘right’ [-Wunused-variable] int right = 0 , left = 0 ; ^ user.cpp:53:18: warning: unused variable ‘left’ [-Wunused-variable] int right = 0 , left = 0 ; ^