Compilare: user.cpp: In function ‘int main()’: user.cpp:79:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= strlen(aux)-1; i++) ^ user.cpp:87:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= strlen(aux)-1; i++) ^ user.cpp:72:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("swap.in", "r", stdin); ^ user.cpp:73:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("swap.out", "w", stdout); ^