Compilare: user.cpp: In function ‘void Back(int, int, int)’: user.cpp:38:10: warning: variable ‘ok’ set but not used [-Wunused-but-set-variable] bool ok = false; ^ user.cpp: At global scope: user.cpp:64:5: warning: first argument of ‘int main(char)’ should be ‘int’ [-Wmain] int main(char args) { ^ user.cpp:64:5: warning: ‘int main(char)’ takes only zero or two arguments [-Wmain]