Compilare: user.cpp: In function ‘int main()’: user.cpp:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘int system(const char*)’, declared with attribute warn_unused_result