안녕하세요 요새 자바를 공부하고있는 하카세입니다 ㅠㅠ
다름이 아니라 제가 자바로 학점을 계산하는 문제를 푸는데 제가 지정한 n3와 n4가 정의가 되지 않았다고 오류가 뜨는데
Switch문 내에서 n3와 n4를 정의를 내린거라고 판단을 했는데.. 제가 제대로 이해를 못하고있나봅니다 흑..
여쭤 볼 사람이 없어서 난감하네요.. 피지알여러분께 도움을 요청합니다

char letterGrade1 = keyboard.next().charAt(0);
double n1 = keyboard.nextInt();
char letterGrade2 = keyboard.next().charAt(0);
double n2 = keyboard.nextInt();// get user input value from keyboard and assign it into n2
double n3, n4; //it will be used in defining GPA
switch (letterGrade1)            {
                    case 'A' :
                            n3 = 4.0;
                            break;
                    case 'B' :
                            n3 = 3.0;
                            break;
                    case 'C' :
                            n3 = 2.0;
                            break;
                    case 'D' :
                            n3 = 1.0;
                            break;
                    case 'F' :
                            n3 = 0.0;
                            break;
                default :
                                        break;
            }
            switch (letterGrade2)             {
                    case 'A' :
                            n3 = 4.0;
                            break;
                    case 'B' :
                            n4 = 3.0;
                            break;
                    case 'C' :
                            n4 = 2.0;
                            break;
                    case 'D' :
                            n4 = 1.0;
                            break;
                    case 'F' :
                            n4 = 0.0;
                            break;
                default :
                        break;
             }
double GPA = (n3+n4)/2;