diff --git a/CPlusPlus20ForProgrammers-master/examples/ch06/a.out b/CPlusPlus20ForProgrammers-master/examples/ch06/a.out
new file mode 100755
index 0000000..f625659
Binary files /dev/null and b/CPlusPlus20ForProgrammers-master/examples/ch06/a.out differ
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_01.cpp b/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_01.cpp
index b43e941..86fadd8 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_01.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_01.cpp
@@ -1,62 +1,41 @@
-// fig06_01.cpp
-// Initializing an array's elements to zeros and printing the array.
-//#include <../libraries/fmt/include/format.h> // C++20: This will be #include <format>
-#include <iostream>
-#include <array>
-#include <vector>
-#include <string>
-
-template <typename T>
-void printArray(T& a, std::string tag){
-   std::cout << "Element       Value --->  "<<tag <<"\n" ;
-
-   // output each array element's value
-   for (size_t i{0}; i < a.size(); ++i) {
-      std::cout <<  i << a[i]<<"\n";
+//variable scope
+#include<iostream>
+//global variable
+//local variable
+int k=0;
+//function
+//array
+//struct
+//class
+//Macro
+int main()
+{ //block
+   cout<<k;
+   int k = 2;
+   int j=0;
+   {
+      int i=0;
    }
+   cout<<k;
+   cout<<::k;
 }
-int main() {
-   std::array<int, 5> values{}; // values is an array of 5 int values
-   std::array<double,10> floatarray;
-   std::vector<double> floatvector(20, 0);
-   for (size_t i{0}; i < floatarray.size(); i++)
-        floatarray[i] = i*i/10.0;
-        
-   // initialize elements of array values to 0        
-   for (size_t i{0}; i < values.size(); ++i) {
-      values[i] = i*i; // set element at location i to 0
-   }
+//definition
+short 2B
+unsigned int 4B
+signed long 8B
 
-   printArray(values,"values");
-   printArray(floatarray,"floatarray");
-   printArray(floatvector, "floatvector");
-   std::cout <<  "Element      Value\n" << "\n";
-    
-   floatvector.resize(5);
-   printArray(floatvector,"floatvector resized");
-   // access elements via the at member function
-   for (size_t i{0}; i < values.size(); ++i) {
-      std::cout <<  i<<values.at(i) <<"\n";
-   }
-/*   for (auto i : values){
-       std::cout <<  i << values.at(i)<<"\n";
-   }
-   */
-   // accessing an element outside the array's bounds with at
-  // values.at(10); // throws an exception
-}
+1B = 0xFF
 
-/**************************************************************************
- * (C) Copyright 1992-2022 by Deitel & Associates, Inc. and               *
- * Pearson Education, Inc. All Rights Reserved.                           *
- *                                                                        *
- * DISCLAIMER: The authors and publisher of this book have used their     *
- * best efforts in preparing the book. These efforts include the          *
- * development, research, and testing of the theories and programs        *
- * to determine their effectiveness. The authors and publisher make       *
- * no warranty of any kind, expressed or implied, with regard to these    *
- * programs or to the documentation contained in these books. The authors *
- * and publisher shall not be liable in any event for incidental or       *
- * consequential damages in connection with, or arising out of, the       *
- * furnishing, performance, or use of these programs.                     *
- **************************************************************************/
+float
+double
+
+unsigned char
+string 
+bool
+
+int i=10;
+//initialization
+
+long b;
+b=1200;
+//assignement
\ No newline at end of file
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch06/matrix.cpp b/CPlusPlus20ForProgrammers-master/examples/ch06/matrix.cpp
new file mode 100644
index 0000000..a17ee65
--- /dev/null
+++ b/CPlusPlus20ForProgrammers-master/examples/ch06/matrix.cpp
@@ -0,0 +1,57 @@
+#include <iostream>
+#include <array>
+#include <vector>
+
+constexpr size_t rows{4};
+constexpr size_t columns{4};
+void MatVecMul(const std::array<std::array<int, columns>, rows>& A, const std::array<int,columns>& V, std::array<int,rows>& B);
+
+template <typename T, long unsigned int N>
+void MatVecMul_template(const std::array<std::array<T, N>, N>& A, const std::array<T,N>& V, std::array<T,N>& B);
+
+template <typename T, typename U>
+void MatVecMul_templatefull(const T& A, const U& V, U& B);
+
+template <typename T>
+void printArrayTemplate(const T& a);
+
+int main() {
+    std::array A{std::array{1, 2, 3}, std::array{4, 5, 6},std::array{4, 5, 0}};
+    std::array V{1, 2, 3,5};
+    std::array <int,3> B{};
+    MatVecMul_template(A, B, V);
+
+   return 0;
+}
+
+void MatVecMul(const std::array<std::array<int, columns>, rows>& A, const std::array<int,columns>& V, std::array<int,rows>& B){
+     for (int i{0}; i < A.size(); i++)
+        for (int j{0}; j < A[0].size(); j++)
+             B[i]+= A[i][j] * V[j];
+}
+
+template <typename T, long unsigned int N>
+void MatVecMul_template(const std::array<std::array<T, N>, N>& A, const std::array<T,N>& V, std::array<T,N>& B){
+     for (int i{0}; i < A.size(); i++)
+        for (int j{0}; j < A[0].size(); j++)
+             B[i]+= A[i][j] * V[j];
+}
+
+template <typename T>
+void MatVecMul_template(const std::vector<std::vector<T>>& A, const std::vector<T>& V, std::vector<T>& B){
+     for (int i{0}; i < A.size(); i++)
+        for (int j{0}; j < A[0].size(); j++)
+             B[i]+= A[i][j] * V[j];
+}
+
+template <typename T, typename U>
+void MatVecMul_templatefull(const T& A, const U& V, U& B){
+    if (A[0].size() == V.size() && A.size() == B.size() ){
+     for (int i{0}; i < A.size(); i++)
+        for (int j{0}; j < A[0].size(); j++)
+             B[i]+= A[i][j] * V[j];
+    }
+    else{
+        std::cout << "sizes are not compatible!";
+    }
+}
\ No newline at end of file