Compilare: user.cpp: In function ‘std::vector<punct> hull(std::vector<punct>)’: user.cpp:77:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<pct.size();i++) ^ user.cpp:92:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < pct.size(); i++) ^ user.cpp: In function ‘double polygon_area(std::vector<punct>)’: user.cpp:121:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<poly.size()-1;i++) ^ user.cpp: In function ‘int main()’: user.cpp:185:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<hull_ion.size();i++) ^ user.cpp:189:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<hull_vasile.size();i++) ^ user.cpp: In function ‘void citire()’: user.cpp:38:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:41:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&p[i].x,&p[i].y); ^ user.cpp: In function ‘int main()’: user.cpp:139:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gradina.in","r",stdin); ^ user.cpp:140:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gradina.out","w",stdout); ^