二叉树遍历+创建

数组存储二叉树(下标从1开始）。i>时父节点为i/2；当i2<=节点个数时，左子树为i2；当i2+1<=节点个数时，右子数为2i+1

void PreTra(int i){
    if(i >= len)
        return ;
    printf("%c",a[i]);
    PreTra(i*2);
    PreTra(i*2+1);
    return ;    
}

void InTra(int i){
    if(i >= len)
        return ;
    InTra(i*2);
    printf("%c",a[i]);
    InTra(i*2+1);
    return ;    
}

void LaTra(int i){
    if(i >= len)
        return ;
        LaTra(i*2);
    LaTra(i*2+1);
    printf("%c",a[i]);
    return ;    
}


int main(){
    int i;
    char ch;
    len = 1;
    while(ch = getchar()){
        a[len++] = ch;
        if(ch == '\n')
            break;
    }
    len --;
    PreTra(1);
    printf("\n");
    InTra(1);
    printf("\n");
    LaTra(1);
    return 0; 
}

先序递归创建二叉树（链表）

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
using namespace std;
struct node{
    char data;
    node * left;
    node * right;
};

void CreateTree(node ** p){
    char ch = getchar();
    if(ch == ' '){
        *p = NULL;
        return ;
    }
    (*p) = (node*) malloc(sizeof(node));
    (*p)->data = ch;
    CreateTree(&((*p)->left));
    CreateTree(&((*p)->right));
}

void PreTra(node *p){
    if(!p)
        return ;
    printf("%c",p->data);
    PreTra(p->left);
    PreTra(p->right);
}

int main(){
    char ch;
    node * tree;
    CreateTree(&tree);
    PreTra(tree);
//  printf("Tree\n");
    return 0;
}

转载于:https://www.cnblogs.com/jxgapyw/p/5292648.html