Compilare: user.cpp: In function ‘int main()’: user.cpp:62:49: warning: left operand of comma operator has no effect [-Wunused-value] int detp=det(a1,b1,a2,b2),det1=(a1,-c1,a2,-c2),det2=det(-c1,b1,-c2,b2); ^ user.cpp:62:52: warning: right operand of comma operator has no effect [-Wunused-value] int detp=det(a1,b1,a2,b2),det1=(a1,-c1,a2,-c2),det2=det(-c1,b1,-c2,b2); ^ user.cpp:62:56: warning: right operand of comma operator has no effect [-Wunused-value] int detp=det(a1,b1,a2,b2),det1=(a1,-c1,a2,-c2),det2=det(-c1,b1,-c2,b2); ^ user.cpp:50:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("geometry.in","r",stdin); ^ user.cpp:51:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("geometry.out","w",stdout); ^ user.cpp:53:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:55:84: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i=1;i<=n;i++) scanf("%d %d %d %d",&t[i].x1,&t[i].y1,&t[i].x2,&t[i].y2); ^