Compilare: user.cpp: In function ‘int main()’: user.cpp:22:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j; ^ user.cpp:22:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:27:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &a, &b); ^