Compilare: user.cpp: In function ‘int main()’: user.cpp:17:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(st.size()>0&&a[st.back()]=='('&&a[i]==')') ^ user.cpp:18:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] urm[st.back()]=i+1,st.pop_back(); ^ user.cpp:12:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.in","r",stdin); ^ user.cpp:13:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.out","w",stdout); ^ user.cpp:14:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a+1); ^ /tmp/ccXFeeGJ.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.