c语言的树数据结构实现_c语言树形结构实现管理功能

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

typedef struct Node Node;

// Defines a node in a binary tree string integers

struct Node {
    long item;
    int count;
    Node *pLeft;
    Node *pRight;

};

// Function prototypes
Node *create_node(long value);
Node *add_node(long value, Node *pNode);
void list_nodes(Node *pNode);
void free_nodes(Node *pNode);

// Function main - execution starts here
int main(void) {

    long newvalue = 0;
    Node *pRoot = NULL;
    char answer = 'n';
    do{
        printf("Enter the node value: ");
        scanf(" %ld", &newvalue);
        if(!pRoot) {
            pRoot = create_node(newvalue);
        } else {
            add_node(newvalue, pRoot);
        }
        printf("Do you want to enter another (y or n)? ");
        scanf(" %c", &answer);
    } while(tolower(answer) == 'y');

    printf("The values in ascending sequence are:\n");
    list_nodes(pRoot);
    free_nodes(pRoot);

    return 0;
}


// Create a binary tree node
Node *create_node(long value) {
    Node *pNode = malloc(sizeof(Node));
    pNode->item = value;
    pNode->count = 1;
    pNode->pLeft = pNode->pRight = NULL;
    return pNode;
}

// Add a new node to the tree
Node *add_node(long value, Node *pNode) {
    if(!pNode) {
        return create_node(value);
    }
    if(value == pNode->item) {
        ++pNode->count;
        return pNode;
    }
    if(value < pNode->item) {
        if(!pNode->pLeft) {
            pNode->pLeft = create_node(value);
            return pNode->pLeft;
        } else {
            return add_node(value, pNode->pLeft);
        }
    } else {
        if(!pNode->pRight) {
            pNode->pRight = create_node(value);
            return pNode->pRight;
        } else {
            add_node(value, pNode->pRight);
        }
    }
}

// List the node values in ascending sequence
void list_nodes(Node *pNode) {
    if(pNode->pLeft)
        list_nodes(pNode->pLeft);

    printf("%10d x %10ld\n", pNode->count, pNode->item);

    if(pNode->pRight)
        list_nodes(pNode->pRight);
}

// Release memory allocated to nodes
void free_nodes(Node *pNode) {
    if(!pNode)
        return;

    if(pNode->pLeft)
        free_nodes(pNode->pLeft);

    if(pNode->pRight)
        free_nodes(pNode->pRight);

    return free(pNode);
}

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输入和输出结果

Enter the node value: 
Do you want to enter another (y or n)? y
Enter the node value: 2
Do you want to enter another (y or n)? y
Enter the node value: 3
Do you want to enter another (y or n)? y
Enter the node value: 555
Do you want to enter another (y or n)? y
Enter the node value: 44
Do you want to enter another (y or n)? y
Enter the node value: 2
Do you want to enter another (y or n)? y
Enter the node value: 1
Do you want to enter another (y or n)? y
Enter the node value: 44
Do you want to enter another (y or n)? n
The values in ascending sequence are:
         2 x          1
         2 x          2
         1 x          3
         2 x         44
         1 x        555
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