Something

	if (score <= 100 && score >= 0) 		if (score >= 70 && score <= 100)			if (score >= 77 && score <= 100)				if (score >= 87 && score <= 100)					if (score >= 94 && score <= 100)					            grade = 'A';						else					  grade = 'B';				else					grade = 'C';			else				grade = 'D';		else			grade = 'F';	else                cout << "Invalid input!\n";                cout << "Grade must be between 0 and 100!\n";