Compilare: user.cpp: In function ‘int main()’: user.cpp:13:10: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:14:7: warning: unused variable ‘k’ [-Wunused-variable] int k; ^ user.cpp:17:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &N); ^ user.cpp:19:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &nr); ^