W3Schools Tryit Editor

Python

Java

​x
 
class TreeNode:    def __init__(self, data):        self.data = data        self.left = None        self.right = None​def preOrderTraversal(node):    if node is None:        return    print(node.data, end=", ")    preOrderTraversal(node.left)    preOrderTraversal(node.right)​root = TreeNode('R')nodeA = TreeNode('A')nodeB = TreeNode('B')nodeC = TreeNode('C')nodeD = TreeNode('D')nodeE = TreeNode('E')nodeF = TreeNode('F')nodeG = TreeNode('G')​root.left = nodeAroot.right = nodeB​nodeA.left = nodeCnodeA.right = nodeD​nodeB.left = nodeEnodeB.right = nodeF​nodeF.left = nodeG​# TraversepreOrderTraversal(root)​#Python

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

typedef struct TreeNode {
    char data;
    struct TreeNode* left;
    struct TreeNode* right;
} TreeNode;

TreeNode* createNewNode(char data) {
    TreeNode* newNode = (TreeNode*)malloc(sizeof(TreeNode));
    newNode->data = data;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}

void preOrderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    printf("%c, ", root->data);
    preOrderTraversal(root->left);
    preOrderTraversal(root->right);
}

int main() {
    TreeNode* root = createNewNode('R');
    TreeNode* nodeA = createNewNode('A');
    TreeNode* nodeB = createNewNode('B');
    TreeNode* nodeC = createNewNode('C');
    TreeNode* nodeD = createNewNode('D');
    TreeNode* nodeE = createNewNode('E');
    TreeNode* nodeF = createNewNode('F');
    TreeNode* nodeG = createNewNode('G');

root->left = nodeA;
    root->right = nodeB;

nodeA->left = nodeC;
    nodeA->right = nodeD;

nodeB->left = nodeE;
    nodeB->right = nodeF;

nodeF->left = nodeG;

// Traverse
    preOrderTraversal(root);

free(nodeG);
    free(nodeF);
    free(nodeE);
    free(nodeB);
    free(nodeC);
    free(nodeD);
    free(nodeA);
    free(root);

return 0;
}

//C

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#include <stdio.h>#include <stdlib.h>​typedef struct TreeNode {    char data;    struct TreeNode* left;    struct TreeNode* right;} TreeNode;​TreeNode* createNewNode(char data) {    TreeNode* newNode = (TreeNode*)malloc(sizeof(TreeNode));    newNode->data = data;    newNode->left = NULL;    newNode->right = NULL;    return newNode;}​void preOrderTraversal(TreeNode* root) {    if (root == NULL) {        return;    }    printf("%c, ", root->data);    preOrderTraversal(root->left);    preOrderTraversal(root->right);}​int main() {    TreeNode* root = createNewNode('R');    TreeNode* nodeA = createNewNode('A');    TreeNode* nodeB = createNewNode('B');    TreeNode* nodeC = createNewNode('C');    TreeNode* nodeD = createNewNode('D');    TreeNode* nodeE = createNewNode('E');    TreeNode* nodeF = createNewNode('F');    TreeNode* nodeG = createNewNode('G');​    root->left = nodeA;    root->right = nodeB;​    nodeA->left = nodeC;    nodeA->right = nodeD;​    nodeB->left = nodeE;    nodeB->right = nodeF;​

public class Main {
    
    public static class TreeNode {
        String data;
        TreeNode left;
        TreeNode right;

public TreeNode(String data) {
            this.data = data;
            this.left = null;
            this.right = null;
        }
    }

public static void preOrderTraversal(TreeNode node) {
        if (node == null) {
            return;
        }
        System.out.print(node.data + ", ");
        preOrderTraversal(node.left);
        preOrderTraversal(node.right);
    }

public static void main(String[] args) {
        TreeNode root = new TreeNode("R");
        TreeNode nodeA = new TreeNode("A");
        TreeNode nodeB = new TreeNode("B");
        TreeNode nodeC = new TreeNode("C");
        TreeNode nodeD = new TreeNode("D");
        TreeNode nodeE = new TreeNode("E");
        TreeNode nodeF = new TreeNode("F");
        TreeNode nodeG = new TreeNode("G");

root.left = nodeA;
        root.right = nodeB;

nodeA.left = nodeC;
        nodeA.right = nodeD;

nodeB.left = nodeE;
        nodeB.right = nodeF;

nodeF.left = nodeG;

// Traverse
        preOrderTraversal(root);
    }
}

// Java

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public class Main {        public static class TreeNode {        String data;        TreeNode left;        TreeNode right;​        public TreeNode(String data) {            this.data = data;            this.left = null;            this.right = null;        }    }​    public static void preOrderTraversal(TreeNode node) {        if (node == null) {            return;        }        System.out.print(node.data + ", ");        preOrderTraversal(node.left);        preOrderTraversal(node.right);    }​    public static void main(String[] args) {        TreeNode root = new TreeNode("R");        TreeNode nodeA = new TreeNode("A");        TreeNode nodeB = new TreeNode("B");        TreeNode nodeC = new TreeNode("C");        TreeNode nodeD = new TreeNode("D");        TreeNode nodeE = new TreeNode("E");        TreeNode nodeF = new TreeNode("F");        TreeNode nodeG = new TreeNode("G");​        root.left = nodeA;        root.right = nodeB;​        nodeA.left = nodeC;        nodeA.right = nodeD;​        nodeB.left = nodeE;        nodeB.right = nodeF;​        nodeF.left = nodeG;​        // Traverse