Compilare: user.cpp: In function ‘void read()’: user.cpp:29:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<=strlen(b); i++) ^ user.cpp: In function ‘void remake()’: user.cpp:61:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘void write()’: user.cpp:72:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^