Compilare: user.cpp: In function ‘int main()’: user.cpp:75:42: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (i != l && j != l && (fabs(point[i].angle - point[j].angle) > EPS) || (point[l].angle < point[j].angle || (l < j && l < i))) { ^ user.cpp:89:21: warning: unused variable ‘a’ [-Wunused-variable] int a = point[j].y - point[i].y; ^ user.cpp:90:21: warning: unused variable ‘b’ [-Wunused-variable] int b = point[i].x - point[j].x; ^