Compilare: user.cpp: In function ‘void read(int&)’: user.cpp:31:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<s.length();i++) x=x*10+code(s[i]); ^ user.cpp: In function ‘void Read(func&)’: user.cpp:37:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(;p<s.length();p++) x.op+=s[p]; ^ user.cpp: In function ‘int code(char)’: user.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int Factor()’: user.cpp:56:12: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] return x; ^