code for exam 2019

bst.c

@@ -0,0 +1,73 @@
+#include <stdio.h> 
+#include<stdlib.h> 
+  
+/* A binary tree node has data, pointer to left child  
+   and a pointer to right child */
+struct node  
+{ 
+    int data; 
+    struct node* left; 
+    struct node* right; 
+}; 
+
+struct node* newNode(int data)  
+{ 
+  struct node* node = (struct node*) 
+                       malloc(sizeof(struct node)); 
+  node->data  = data; 
+  node->left  = NULL; 
+  node->right = NULL; 
+    
+  return(node); 
+} 
+
+struct node* insert(struct node* node, int data)  
+{ 
+  /* 1. If the tree is empty, return a new,      
+      single node */
+  if (node == NULL)  
+    return(newNode(data));   
+  else 
+  { 
+    /* 2. Otherwise, recur down the tree */
+    if (data <= node->data)  
+        node->left  = insert(node->left, data); 
+    else 
+        node->right = insert(node->right, data); 
+    
+    /* return the (unchanged) node pointer */
+    return node;  
+  } 
+} 
+
+int minValue(struct node* node) { 
+  struct node* current = node; 
+  
+  /* loop down to find the leftmost leaf */
+  while (current->left != NULL) { 
+    current = current->left; 
+  } 
+  return(current->data); 
+} 
+
+
+void deleteTree(struct node* node)  
+{ 
+    if (node == NULL) return; 
+  
+    /* first delete both subtrees */
+    deleteTree(node->left); 
+    deleteTree(node->right); 
+    
+    /* then delete the node */
+    printf("\n Deleting node: %d", node->data); 
+    free(node); 
+}  
+
+int size(struct node* node)  
+{   
+  if (node==NULL)  
+    return 0; 
+  else     
+    return(size(node->left) + 1 + size(node->right));   
+}