Compilare: user.cpp: In function ‘int valid()’: user.cpp:31:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:68:21: warning: ignoring return value of ‘int system(const char*)’, declared with attribute warn_unused_result [-Wunused-result] system ("PAUSE"); ^