Compilare: user.cpp: In function ‘int main()’: user.cpp:6:40: warning: ‘x4’ may be used uninitialized in this function [-Wmaybe-uninitialized] int s=x1*y2+x2*y3+y1*x3-y2*x3-y3*x1-y2*x2; ^ user.cpp:13:19: note: ‘x4’ was declared here int n,i,x1,x2,x3,x4,y1,y2,y3,y4,d1,d2,d3; ^ user.cpp:6:40: warning: ‘y4’ may be used uninitialized in this function [-Wmaybe-uninitialized] int s=x1*y2+x2*y3+y1*x3-y2*x3-y3*x1-y2*x2; ^ user.cpp:13:31: note: ‘y4’ was declared here int n,i,x1,x2,x3,x4,y1,y2,y3,y4,d1,d2,d3; ^