Compilare: user.cpp: In function ‘int main()’: user.cpp:23:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v.size()-2;i++) ^ user.cpp:24:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<v.size()-1;j++) ^ user.cpp:11:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrtri.in","r",stdin); ^ user.cpp:12:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrtri.out","w",stdout); ^ user.cpp:15:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:18:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^