Compilare: user.cpp: In instantiation of ‘void Floyd<T>::build() [with T = int]’: user.cpp:51:14: required from here user.cpp:16:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= n; i++) { ~~^~~~ user.cpp:20:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G.size(); i++) user.cpp:24:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k <= n; k++) ~~^~~~ user.cpp:25:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= n; i++) ~~^~~~ user.cpp:26:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j <= n; j++) ~~^~~~ user.cpp: In function ‘int main()’: user.cpp:62:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.in", "r", stdin); ^ user.cpp:63:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.out", "w", stdout); ^