Compilare: user.cpp: In function ‘double hull()’: user.cpp:61:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<b.size();i++) ^ user.cpp:74:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:85:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("geometrie.in", "r", stdin); ^ user.cpp:86:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("geometrie.out", "w", stdout); ^ user.cpp:92:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i",&a[i].x, &a[i].y); ^ user.cpp:96:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i",&qx, &qy); ^