Compilare: user.cpp: In function ‘int main()’: user.cpp:10: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:16: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:13: warning: ‘a’ may be used uninitialized in this function