C - 嵌套链表

Question

我正在尝试创建一个学生链接列表，每个学生都有一个成绩链接列表，但我无法访问学生链接列表中的成绩链接列表。

typedef struct student_data_struct{
    char student[MAX];
    struct grades_list_struct *gradeP;
} student_Data;

typedef struct student_list_struct{
    student_Data studentData;
    struct student_list_struct *next;
} StudentNode;

typedef struct grades_list_struct{
    int grade;
    struct grades_list_struct *next;
} GradeNode;

GradeNode *insertGrade(int grade, GradeNode *head){
    GradeNode *newNode=NULL;
    newNode=(GradeNode*)calloc(1, sizeof(GradeNode));

    if(head!=NULL){
        newNode->grade=grade;
        newNode->next=head;
        return newNode;
    } else {
        newNode->grade=grade;
        newNode->next=NULL;
        return newNode;
    }
}

StudentNode *insertStudent(char studentName[MAX], int studentGrade, StudentNode *head){
    StudentNode *newNode=NULL;
    newNode=(StudentNode*)calloc(1, sizeof(StudentNode));
    newNode->studentData->gradeP=(GradeNode*)calloc(1, sizeof(GradeNode));

    if (head==NULL){
        strcpy(newNode->studentData.student, studentName);
        newNode->next=NULL;
        newNode->studentData->gradeP=insertGrade(studentGrade, newNode->studentData->gradeP);
        return newNode;
    } else {
        strcpy(newNode->student, studentName);
        newNode->gradeP->grade=studentGrade;
        newNode->studentData->gradeP=insertGrade(studentGrade, newNode->studentData->gradeP);
        return newNode;
    }
}

当我尝试为成绩指针分配内存时，

newNode->studentData->gradeP=(GradeNode*)calloc(1, sizeof(GradeNode));

我收到错误：

error: invalid type argument of '->' (have 'student_Data' {aka 'struct student_data_struct'})

同样，当我尝试为学生插入成绩时，

newNode->studentData->gradeP=insertGrade(studentGrade, newNode->studentData->gradeP);

我收到错误：

error: invalid type argument of '->' (have 'student_Data' {aka 'struct student_data_struct'})

如有任何帮助，我们将不胜感激。

Answer 1

studentData是struct类型，不是指向struct的指针。因此，必须使用 struct(.) 的成员访问运算符而不是运算符来访问指向 struct(->).

的指针的成员。

Answer 2

您正在访问一个带有指针符号的结构成员。尝试如下所示编写：-

newNode->studentData.gradeP=(GradeNode*)calloc(1, sizeof(GradeNode));

newNode->studentData.gradeP=insertGrade(studentGrade, newNode->studentData.gradeP);

C - 嵌套链表

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