Compilare: user.cpp: In function ‘int is(std::string, int, int, int)’: user.cpp:24:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<op.size();++i) { ^ user.cpp: In function ‘int eval(int, int)’: user.cpp:41:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int t = 0;t < ops.size();++t) { ^ user.cpp: In function ‘int make(std::string, int, int)’: user.cpp:37:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:76:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in","r",stdin); ^ user.cpp:77:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out","w",stdout); ^