Compilare: user.cpp: In function ‘int main()’: user.cpp:37:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= strlen(s); i++) ^ user.cpp:26:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("text.in", "r", stdin); ^ user.cpp:27:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("text.out", "w", stdout); ^ /tmp/ccKJ6HeC.o: In function `main': user.cpp:(.text.startup+0x68): warning: the `gets' function is dangerous and should not be used.