An example of a multi-fork tree

#include "stdio.h"
#include "stdlib.h"

#define new(Class) (Class*)malloc(sizeof(Class))  

typedef struct node Node;
struct node{
	Node *next;
	Node *nextLayer; //If there is an address, it means there is a next layer of linked list 	
	int num;
};

//Get a 4-level multi-fork example tree
Node* createTree(){
	//statement
	Node* head;
	Node* layer2;
	Node * layer3_1;
	Node * layer3_2;
	//Construct the first layer (root)
	head =  new(Node);
	head->num = 1;
	head->next = NULL;
	//construct the second layer
	layer2 = new(Node);
	layer2->num = 2;
	layer2->next = new(Node);
	
	layer2->next->num = 3;
	layer2->next->nextLayer = NULL;
	layer2->next->next = new(Node);
	
	layer2->next->next->num = 4;
	layer2->next->next->next = NULL;
	head->nextLayer = layer2; //The root node (the node whose num is 1) is connected to the second layer (the node whose num is 2)
	//Construct the third layer_first paragraph
	layer3_1 = new(Node);
	layer3_1->num = 5;
	layer3_1->nextLayer = NULL;
	layer3_1->next = new(Node);
	
	layer3_1->next->num = 6;
	layer3_1->next->nextLayer = NULL;
	layer3_1->next->next = NULL;
	layer2->nextLayer = layer3_1; //The second layer (node ​​with num 2) connects to the third layer_first segment (node ​​with num 5)
	//Construct the third layer_second segment
	layer3_2 = new(Node);
	layer3_2->num = 7;
	layer3_2->nextLayer = NULL;
	layer3_2->next = new(Node);
	
	layer3_2->next->num = 8;
	layer3_2->next->nextLayer = NULL;
	layer3_2->next->next = new(Node);
	
	layer3_2->next->next->num = 9;
	layer3_2->next->next->nextLayer = NULL;
	layer3_2->next->next->next = new(Node);
	
	layer3_2->next->next->next->num = 10;
	layer3_2->next->next->next->nextLayer = NULL;
	layer3_2->next->next->next->next = NULL;
	layer2->next->next->nextLayer = layer3_2; //The second layer (node ​​with num 4) connects to the third layer_second segment (node ​​with num 7)
	return head;
}

// preorder read
void read(Node* head){
	Node* cursor = head;
	/** Traverse the data of each node,
	   When encountering a node with the next layer, directly call this function to read the next layer of the current node,
	   After reading the next layer, continue to read the next node in the last loop. It is recommended to draw a recursive process to understand**/
	while(cursor != NULL) {
		printf("%d\n", cursor->num);
		if(cursor->nextLayer != NULL) {
			read(cursor->nextLayer);
		}
		cursor = cursor->next;
	}
}


int main(){
	read(createTree());
	return 0;
}