Compilare: user.cpp: In function ‘double area(int)’: user.cpp:12:18: warning: unused variable ‘x3’ [-Wunused-variable] double x1,x2,x3,y2,y3,s; ^ user.cpp:22:43: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] s += (x2*point[1].y - point[1].x * y2); ^ user.cpp:22:38: warning: ‘y2’ may be used uninitialized in this function [-Wmaybe-uninitialized] s += (x2*point[1].y - point[1].x * y2); ^ user.cpp:22:13: warning: ‘x2’ may be used uninitialized in this function [-Wmaybe-uninitialized] s += (x2*point[1].y - point[1].x * y2); ^