Compilare: user.cpp: In function ‘int main()’: user.cpp:89:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.in", "r", stdin); ^ user.cpp:90:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.out", "w", stdout); ^ user.cpp:92:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s + 1); ^ /tmp/cc57EIlz.o: In function `main': user.cpp:(.text.startup+0x55): warning: the `gets' function is dangerous and should not be used.