Compilare: In file included from /usr/include/c++/4.8/cassert:43:0, from /usr/include/i386-linux-gnu/c++/4.8/bits/stdc++.h:33, from user.cpp:1: user.cpp: In function ‘int main()’: user.cpp:30:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] assert(S.size() <= n); ^ user.cpp:15:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("streetcrypto.in", "r", stdin); ^ user.cpp:16:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("streetcrypto.out", "w", stdout); ^ user.cpp:18:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:22:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:24:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &x[i]); ^