Compilare: user.cpp: In function ‘int is(std::string, int, int, int)’: user.cpp:15:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(loc + op.size() - 1 > dr) return 0; ^ user.cpp:17:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<op.size() && ok;++i) { ^ user.cpp: In function ‘int eval(int, int, int)’: user.cpp:30:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int t = lvl;t<ops.size();++t) { ^ user.cpp: In function ‘std::string getp(std::string)’: user.cpp:62:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();++i) { ^ user.cpp: In function ‘int make(std::string, int, int)’: user.cpp:27:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int eval(int, int, int)’: user.cpp:52:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:88:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("logic.in","r",stdin); ^ user.cpp:89:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("logic.out","w",stdout); ^