cprogram and pointers

README.md

@@ -23,6 +23,27 @@ If T(n) is the run time , Cop is the cost of basic operation and C(n) is the num
 
     T(n) ≈ Cop ⨉ C(n)
 
+### Prereq
+Check if gdb is installed and updated
+
+    sudo apt-get install build-essential gdb
+
+    build-essential is already the newest version (12.4ubuntu1).
+    gdb is already the newest version (8.1.1-0ubuntu1).
+
+check if gcc is updated too
+
+    gcc -v
+
+    Using built-in specs.
+    COLLECT_GCC=gcc
+    COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
+    OFFLOAD_TARGET_NAMES=nvptx-none
+    OFFLOAD_TARGET_DEFAULT=1
+    Target: x86_64-linux-gnu
+    Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.5.0-3ubuntu1~18.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
+    Thread model: posix
+    gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04) 
 
 ### Compiling a C program 
 The phases  of gcc Compiler converts a C program into an executable. 
@@ -70,4 +91,4 @@ Sites
 Books 
 - Introduction to Algorithms by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein( CLRS )
     - MIT press - Introduction to Algorithms, Third Edition https://mitpress.mit.edu/books/introduction-algorithms-third-edition
-    
+- https://code.visualstudio.com/docs/cpp/config-linux 

binarytree_algorithms/bt_insert_delete.cpp

@@ -51,7 +51,7 @@ void inorder(node* temp){
 }
 
 // ----------------------- 
-
+// Insert in level order 
 // iterative level order traversal in BT of the given tree using queue to find a node with a null child
 node* insert_levelorder(node* root, int newdata){
 

binarytree_algorithms/isomorphic_bt.cpp

@@ -1,6 +1,8 @@
 #include<iostream>
 using namespace std;
 
+// ISO morphic /  idenical trees  
+
 struct node{
     int data;
     struct node* left;
@@ -20,6 +22,26 @@ bool isidentical(struct node * root1 , struct node * root2){
     return isidentical(root1->left,root2->left) && isidentical(root1->right, root2->right);
 }
 
+// Mirrorrs the tree 
+void mirrorTree(struct node* root){
+    if( root ==NULL) return;
+    struct node* temp;
+    mirrorTree(root->left);
+    mirrorTree(root->right);
+    temp = root->left;          // swap(node->left, node->right);
+    root->left = root->right;
+    root->right = temp;                        
+}
+
+void printTree(struct node* node) {
+   if (node == NULL) {
+      return;
+   }
+   printTree(node->left);
+   cout << node->data << " ";
+   printTree(node->right);
+}
+
 int main(){
     struct node* root1 = new node(10);
     root1->left = new node(30);
@@ -31,4 +53,9 @@ int main(){
 
     cout << isidentical(root1,root2);
 
+    cout << "\n orgnal tree "<< endl;
+    printTree(root1); 
+    mirrorTree(root1);
+    cout << "\n mirror of tree " <<endl;
+    printTree(root1);
 }

binarytree_algorithms/isperfect_bt.cpp

@@ -1,5 +1,69 @@
-// Is the binary tree perfect 
+// Is binary tree perfect 
+//A Binary tree is a Perfect Binary Tree in which all internal nodes have two children 
+// and all leaves are at the same level.
+
+// NOT WORKING
+#include <iostream>
+#include<queue>
+using namespace std;
+
+struct node{
+    int data; 
+    struct node* left;
+    struct node* right;
+    node(int value){
+        data = value;
+        left = NULL;
+        right = NULL;        
+    }
+};
+void addEdge(struct node* root , int key){
+    if(root == NULL){
+        root = new node(key);
+    }else if(key > root->data){
+         addEdge(root->right, key);
+    }else{
+         addEdge(root->left, key);
+    }
+}
 
 
 // approach 1 :
-// Iterative approach to check if a Binary Tree is Perfect
+// Iterative approach to check if a Binary Tree is Perfect
+bool isperfect(node* root){
+    queue<node*> q;
+    q.push(root);
+    int flag=0;
+
+    while (!q.empty()){
+        node * temp = q.front();
+        q.pop();
+
+        if(temp->left && temp->right){
+            if(flag==1){
+                return false;
+            }else{
+                q.push(root->left);
+                q.push(root->right);
+            }
+        }else if(!temp->right && !temp->left){
+            flag=1;
+        }else if(!temp->right || !temp->left){
+            return false;
+        }
+    }
+    return true;
+}
+
+int main(){
+    // int arr[]={5,7,3,6,2,9};
+    int arr[]={1,2,3,4};
+    int n = sizeof(arr)/sizeof(arr[0]);
+
+    struct node* root= new node(arr[0]);
+    for(int i=1;i<n;i++){
+        addEdge(root,arr[i]);
+    }
+
+    cout << isperfect(root);
+}