Merge pull request Harshsngh07#41 from 007kartik-bot-1/master

Added tree traversal using recursion

Language/C/treeTraversalRecur/stack.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "stack.h"
+#include "tree.h"
+
+node *getNode(tree *c)
+{
+  node *nn = (node *)malloc(sizeof(node));
+  nn->next = NULL;
+  nn->top = c;
+  return nn;
+}
+
+int isempty(node *st)
+{
+  if (st == NULL)
+    return 1;
+  return 0;
+}
+
+void push(tree *adr, node **st)
+{
+  node *nn = getNode(adr);
+  nn->next = (*st);
+  (*st) = nn;
+}
+
+void pop(node **st)
+{
+  if (isempty(*st))
+  {
+    printf("Stack empty can't pop");
+  }
+  node *temp = (*st);
+  (*st) = (*st)->next;
+  free(temp);
+}
+
+void display(node *st)
+{
+  while (!isempty(st))
+  {
+    printf("%c ", st->top);
+    st = st->next;
+  }
+  printf("\n");
+}

Language/C/treeTraversalRecur/stack.h

@@ -0,0 +1,18 @@
+#ifndef STACK_HEADER
+#define STACK_HEADER
+
+#include "tree.h"
+
+typedef struct Node
+{
+  tree *top;
+  struct Node *next;
+} node;
+
+node *getNode(tree *c);
+void display(node *st);
+int isempty(node *st);
+void push(tree *adr, node **st);
+void pop(node **st);
+
+#endif

Language/C/treeTraversalRecur/tree.c

@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "tree.h"
+
+tree *getTreeNode(int data)
+{
+  tree *nn = (tree *)malloc(sizeof(tree));
+  nn->left = nn->right = NULL;
+  nn->data = data;
+  return nn;
+}
+
+tree *insert(tree *root, int data)
+{
+  if (!root)
+  {
+    return getTreeNode(data);
+  }
+  else if (root->data < data)
+  {
+    root->right = insert(root->right, data);
+  }
+  else
+  {
+    root->left = insert(root->left, data);
+  }
+  return root;
+}
+
+void inorder(tree *root)
+{
+  if (root)
+  {
+    inorder(root->left);
+    printf("%d ", root->data);
+    inorder(root->right);
+  }
+}
+
+void preorder(tree *root)
+{
+  if (root)
+  {
+    printf("%d ", root->data);
+    preorder(root->left);
+    preorder(root->right);
+  }
+}
+
+void postorder(tree *root)
+{
+  if (root)
+  {
+    postorder(root->left);
+    postorder(root->right);
+    printf("%d ", root->data);
+  }
+}

Language/C/treeTraversalRecur/tree.h

@@ -0,0 +1,16 @@
+#ifndef TREE_HEADER
+#define TREE_HEADER
+
+typedef struct Tree
+{
+  int data;
+  struct Tree *left, *right;
+} tree;
+
+tree *insert(tree *root, int data);
+void inorder(tree *root);
+void postorder(tree *root);
+void preorder(tree *root);
+void inorder(tree *root);
+
+#endif

Language/C/treeTraversalRecur/treeTraversal.c

@@ -0,0 +1,60 @@
+// to run type "gcc treeTraversal.c tree.c stack.c"
+// then run the executable file and enter your input
+
+#include <stdio.h>
+
+#include "tree.h"
+#include "stack.h"
+
+void printstack(node *stack)
+{
+  printf("stack: ");
+  while (!isempty(stack))
+  {
+    printf("%p ", stack->top->data);
+  }
+  printf("\n");
+}
+
+int main()
+{
+  tree *root = NULL;
+
+  int n, val;
+  printf("Enter number of nodes: ");
+  scanf("%d", &n);
+
+  for (int i = 0; i < n; i++)
+  {
+    printf("Enter node %d: ", i+1);
+    scanf("%d", &val);
+    root = insert(root, val);
+  }
+
+  //using binary search tree.
+  //for an input of 2 1 4 3 5
+  //           2
+  //         /  \
+  //        1    3 
+  //            / \
+  //           4   5 
+
+  // inorder: 1 2 3 4 5
+  // preorder: 2 1 4 3 5
+  // postorder: 1 3 5 4 2
+
+
+  printf("inorder: ");
+  inorder(root);
+  printf("\n");
+
+  printf("preorder: ");
+  preorder(root);
+  printf("\n");
+
+  printf("postorder: ");
+  postorder(root);
+  printf("\n");
+
+  return 0;
+}