Compilare: user.cpp: In function ‘int main()’: user.cpp:12:25: warning: variable ‘f’ set but not used [-Wunused-but-set-variable] int n, m, i, a, b, x, f, j; ^ user.cpp:12:28: warning: unused variable ‘j’ [-Wunused-variable] int n, m, i, a, b, x, f, j; ^ user.cpp:16:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", &n, &m); ^ user.cpp:18:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", &a, &b); ^