Compilare: user.cpp: In function ‘int sum(int, int)’: user.cpp:19:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int dif(int, int)’: user.cpp:23:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:37:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("greutati.in","r",stdin); ^ user.cpp:38:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("greutati.out","w",stdout); ^