Compilare: user.cpp: In function ‘int main()’: user.cpp:20: warning: format ‘%ld’ expects type ‘long int*’, but argument 3 has type ‘long int’ user.cpp:14: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:20: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:20: warning: ‘lt’ may be used uninitialized in this function