Compilare: user.cpp: In function ‘float line(std::vector<punct>)’: user.cpp:51:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();++i) ^ user.cpp:54:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i+1;j<a.size();++j) ^ user.cpp: In function ‘float divide(std::vector<punct>)’: user.cpp:81:85: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(stop = mij; std::abs(a[mij].x - a[stop].x) < distance && stop < a.size(); stop++); ^ user.cpp: In function ‘int main()’: user.cpp:93:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in", "r", stdin); ^ user.cpp:94:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.out", "w", stdout); ^ user.cpp:95:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:98:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&local.x,&local.y); ^