Eroare de compilare: user.cpp:9:10: error: ‘P’ was not declared in this scope double C(P o,P a,P b) { return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y); } ^ user.cpp:9:14: error: ‘P’ was not declared in this scope double C(P o,P a,P b) { return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y); } ^ user.cpp:9:18: error: ‘P’ was not declared in this scope double C(P o,P a,P b) { return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y); } ^ user.cpp:9:21: error: expression list treated as compound expression in initializer [-fpermissive] double C(P o,P a,P b) { return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y); } ^ user.cpp:9:23: error: expected ‘,’ or ‘;’ before ‘{’ token double C(P o,P a,P b) { return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y); } ^ user.cpp: In function ‘int main()’: user.cpp:17:43: error: ‘C’ cannot be used as a function for(;h>1&&C(v[s[h-1]],v[s[h]],v[i])>0;h--); ^ user.cpp:11:97: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("infasuratoare.in","r",stdin),freopen("infasuratoare.out","w",stdout),scanf("%d",&n); ^ user.cpp:11:97: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] user.cpp:11:97: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] user.cpp:13:93: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&v[i].x,&v[i].y),p=v[i].x<v[p].x||(v[i].x==v[p].x&&v[i].x<v[p].x)?i:p; ^