Compilare: user.c: In function ‘read_matrix’: user.c:91:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, x, y, c; ^ user.c:91:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, x, y, c; ^ user.c:94:12: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", m, n); ^ user.c:101:16: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d%d", &x, &y, &c); ^