• 二叉樹節點類型BTNode：

1 typedef struct node
2 {
3     char data;
4     struct node *lchild, *rchild;
5 } BTNode;

創建二叉樹

 1 void CreateBTree(BTNode *&b, char *str)
 2 {
 3     BTNode *St[MaxSize], *p = NULL;
 4     int top = -1, ch, k, j = 0;
 5     b = NULL;
 6     ch = str[j];
 
 7     while (ch != ‘\0‘)
 8     {
 9         switch (ch)
10         {
11         case ‘(‘: ++top; St[top] = p; k = 1; break;
12         case ‘,‘: k = 2; break;
13         case ‘)‘: --top; break;
14         default: p = (BTNode*)malloc(sizeof(BTNode));
15             p->data = ch;  p->lchild = p->rchild = NULL;
 
16             if (b == NULL)
17                 b = p;
18             else
19             {
20                 switch (k)
21                 {
22                 case 1: St[top]->lchild = p; break;
23                 case 2: St[top]->rchild = p; break;
24                 }
25             }
 
26         }
27         ++j;
28         ch = str[j];
29     }
30 }

輸出二叉樹

 1 void DispBTree(BTNode *b)
 2 {
 3     if (b != NULL)
 4     {
 5         printf(" %c", b ->data);
 6         if (b->lchild != NULL || b->rchild != NULL)
 7         {
 8             printf("(");
 9             DispBTree(b->lchild);
10             if (b->rchild != NULL)
11                 printf(",");
12             DispBTree(b->rchild);
13             printf(")");
14         }
15     }
16 }

二叉樹的高度：

 1 int HeightBTree(BTNode *b)
 2 {
 3     if (b != NULL)
 4     {
 5         int i = HeightBTree(b->lchild);
 6         int j = HeightBTree(b->rchild);
 7         return (i > j ? (i + 1) : (j + 1));
 8     }
 9     return 0;
10 }

二叉樹節點個數

1 int Nodes(BTNode *b)
2 {
3     if (b == NULL)
4         return 0;
5     else if (b->lchild == NULL && b->rchild == NULL)
6         return 1;
7     else
8         return (Nodes(b->lchild) + Nodes(b->rchild) + 1);
9 }

二叉樹葉子節點

1 int LeafNodes(BTNode *b)
2 {
3     if (b == NULL)
4         return 0;
5     else if (b->lchild == NULL && b->rchild == NULL)
6         return 1;
7     else
8         return (LeafNodes(b->lchild) + LeafNodes(b->rchild) );
9 }

cpp

#include<stdio.h>
#include<malloc.h>
#define MaxSize 100
typedef struct node
{
    char data;
    struct node *lchild, *rchild;
} BTNode;

void CreateBTree(BTNode *&b, char *str)
{
    BTNode *St[MaxSize], *p = NULL;
    int top = -1, ch, k, j = 0;
    b = NULL;
    ch = str[j];
    while (ch != ‘\0‘)
    {
        switch (ch)
        {
        case ‘(‘: ++top; St[top] = p; k = 1; break;
        case ‘,‘: k = 2; break;
        case ‘)‘: --top; break;
        default: p = (BTNode*)malloc(sizeof(BTNode));
            p->data = ch;  p->lchild = p->rchild = NULL;
            if (b == NULL)
                b = p;
            else
            {
                switch (k)
                {
                case 1: St[top]->lchild = p; break;
                case 2: St[top]->rchild = p; break;
                }
            }
        }
        ++j;
        ch = str[j];
    }
}

void DispBTree(BTNode *b)
{
    if (b != NULL)
    {
        printf(" %c", b ->data);
        if (b->lchild != NULL || b->rchild != NULL)
        {
            printf("(");
            DispBTree(b->lchild);
            if (b->rchild != NULL)
                printf(",");
            DispBTree(b->rchild);
            printf(")");
        }
    }
}

int HeightBTree(BTNode *b)
{
    if (b != NULL)
    {
        int i = HeightBTree(b->lchild);
        int j = HeightBTree(b->rchild);
        return (i > j ? (i + 1) : (j + 1));
    }
    return 0;
}

int Nodes(BTNode *b)
{
    if (b == NULL)
        return 0;
    else if (b->lchild == NULL && b->rchild == NULL)
        return 1;
    else
        return (Nodes(b->lchild) + Nodes(b->rchild) + 1);
}

int LeafNodes(BTNode *b)
{
    if (b == NULL)
        return 0;
    else if (b->lchild == NULL && b->rchild == NULL)
        return 1;
    else
        return (LeafNodes(b->lchild) + LeafNodes(b->rchild) );
}

int level(BTNode *b)
{

}

int main()
{
    BTNode *b;
    int h;
    char str[] = "A(B(D(G, H)),C(E(,I), F)";
    CreateBTree(b, str);
    printf("二叉樹：");
    DispBTree(b); printf("\n");
    h = HeightBTree(b);
    printf("二叉樹的高度為：%d\n", h);
    
    h = Nodes(b);
    printf("節點個數： %d\n", h);
    h = LeafNodes(b);
    printf("葉子節點個數： %d\n", h);
    return 0;
    

}

【C語言】 二叉樹的基本運算