Compilare: user.cpp: In function ‘long long unsigned int expow(long long unsigned int, long long unsigned int)’: user.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=b;i++) { ~^~~ user.cpp: In function ‘int main()’: user.cpp:71:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trapeze.in","r",stdin); ^ user.cpp:72:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trapeze.out","w",stdout); ^