Compilare: user.cpp: In function ‘int main()’: user.cpp:20:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(ch==')') ^ user.cpp:27:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size()); ^ user.cpp:6:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.in","rt",stdin); ^ user.cpp:7:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.out","wt",stdout); ^