What is the role of ElemType in the C language?

Elemtype is a placeholder used to represent data types in the C language. Its purpose is to allow flexibility in determining the data type to be stored when using generic data structures. By using elemtype, the same code can be used for structures of different data types.

For example, when defining the structure of a linked list, you can use elemtype to represent the data type stored in each node of the linked list, as shown below:

typedef struct ListNode {
    elemtype data;  // 数据
    struct ListNode* next;  // 指向下一个节点的指针
} ListNode;

Different data types can be specified as needed when declaring a linked list node.

ListNode* node1;  // 存储整数类型的节点
ListNode* node2;  // 存储字符类型的节点
ListNode* node3;  // 存储自定义结构体类型的节点

By using elemtype, code reuse and flexibility can be achieved, avoiding the need to write multiple similar codes for different data types of structures.