Compilare: user.cpp: In function ‘int r1()’: user.cpp:62:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size()) ^ user.cpp: In function ‘int r2()’: user.cpp:94:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size()) ^ user.cpp: In function ‘void read()’: user.cpp:120:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size()) ^ user.cpp: In function ‘int r1()’: user.cpp:89:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int r2()’: user.cpp:115:1: warning: control reaches end of non-void function [-Wreturn-type] } ^