Compilare: user.c: In function ‘main’: user.c:7:11: warning: unused variable ‘i’ [-Wunused-variable] long long i, op = 0, M, N, sqr, area; ^ user.c:6:15: warning: variable ‘file2’ set but not used [-Wunused-but-set-variable] FILE *file1, *file2; ^ user.c:12:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &M); ^ user.c:13:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &N); ^