Compilare: user.cpp: In function ‘bool Check(int)’: user.cpp:46:30: 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:46:53: 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:46:84: 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:46:111: 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:48:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( ( v[i].x <= vis[i].second && v[i].y >= vis[i].second ) || ( v[nr].y >= vis[i].first && v[nr].x <= vis[i].first) ) ^ user.cpp:48:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( ( v[i].x <= vis[i].second && v[i].y >= vis[i].second ) || ( v[nr].y >= vis[i].first && v[nr].x <= vis[i].first) ) ^ user.cpp:48:85: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( ( v[i].x <= vis[i].second && v[i].y >= vis[i].second ) || ( v[nr].y >= vis[i].first && v[nr].x <= vis[i].first) ) ^ user.cpp:48:112: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( ( v[i].x <= vis[i].second && v[i].y >= vis[i].second ) || ( v[nr].y >= vis[i].first && v[nr].x <= vis[i].first) ) ^ user.cpp: In function ‘int main()’: user.cpp:61:6: warning: unused variable ‘right’ [-Wunused-variable] int right = 0 , left = 0 ; ^ user.cpp:61:18: warning: unused variable ‘left’ [-Wunused-variable] int right = 0 , left = 0 ; ^