Compilare: user.cpp: In function ‘int main()’: user.cpp:53:40: 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:54:42: 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:59:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ user.cpp: In member function ‘int KSEQ::getval()’: user.cpp:46:5: warning: control reaches end of non-void function [-Wreturn-type] } ^ /tmp/ccIzVDfu.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.