C数据结构与算法测试例子

#include <stdio.h> #include <stdlib.h> struct Node { int data; struct Node* next; struct Node* prev; // Pointer pointing towards next node }; //function to print the doubly linked list void display(struct Node* node) { struct Node *end; printf("List in Forward direction: "); while (node != NULL) { printf(" %d ", node->data); end = node; node = node->next; } printf("\nList in backward direction: "); while (end != NULL) { printf(" %d ", end->data); end = end->prev; } } // main function int main() { //creating 4 pointers of type struct Node //So these can point to address of struct type variable struct Node* head = NULL; struct Node* node2 = NULL; struct Node* node3 = NULL; struct Node* node4 = NULL; // allocate 4 nodes in the heap head = (struct Node*)malloc(sizeof(struct Node)); node2 = (struct Node*)malloc(sizeof(struct Node)); node3 = (struct Node*)malloc(sizeof(struct Node)); node4 = (struct Node*)malloc(sizeof(struct Node)); /* Using malloc method we have created 4 memory blocks Each memory block is of type struct and has int data and Pointer of type Node So it can point towards a node type struct. head node2 node3 node4 | | | | | | | | +---++---+-----+ +----+----+----+ +----+----+----+ +----+----+----+ |prev|data|next| |prev|data|next| |prev|data|next| |prev|data|next| +---++---+-----+ +----+----+----+ +----+----+----+ +----+----+----+ # As of now data has garbage value and its pointer points towards random addresses*/ head->data = 5; // data set for head node head->next = node2; // next pointer assigned to address of node2 head->prev = NULL; node2->data = 10; node2->next = node3; node2->prev = head; node3->data = 12; node3->next = node4; node3->prev = node2; node4->data = 3; node4->next = NULL; node4->prev = node3; //last node assigned to Null as linked list ends here /* head node2 node3 node4 | | | | | | | | +---++---+-----+ +----+----+----+ +----+----+----+ +----+----+----+ |prev| 5 |next|--->|prev| 10 |next|--->|prev| 12 |next|--->|prev| 3 |next| +---++---+-----+ +----+----+----+ +----+----+----+ +----+----+----+ */ display(head); return 0; }