完全二叉树的先根、中根、后根遍历

package demo;

public class P45 {
	//完全二叉树的先根、中根、后根遍历
	static void preOrder(int[] arr,int index){
		if(index>=arr.length)
			return;
		System.out.print(arr[index]+", ");	//先输出根节点
		preOrder(arr,2*index+1);			//左子树
		preOrder(arr,2*index+2);			//右子树
	}
	
	static void inOrder(int[] arr,int index){
		if(index>=arr.length)
			return;
		inOrder(arr,2*index+1);				//左子树
		System.out.print(arr[index]+", ");	//根节点
		inOrder(arr,2*index+2);				//右子树
	}
	
	static void afterOrder(int[] arr,int index){
		if(index>=arr.length)
			return;
		afterOrder(arr,2*index+1);				//左子树
		afterOrder(arr,2*index+2);				//右子树
		System.out.print(arr[index]+", ");		//根节点
	}
	
	public static void main(String[] args) {
		int[] arr= {78,56,34,43,34};
		preOrder(arr,0);
		System.out.println();
		inOrder(arr,0);
		System.out.println();
		afterOrder(arr, 0);
	}

}