diff --git a/CPlusPlus20ForProgrammers-master/examples/ch06/a.out b/CPlusPlus20ForProgrammers-master/examples/ch06/a.out
index bb04439..f593ff9 100755
Binary files a/CPlusPlus20ForProgrammers-master/examples/ch06/a.out and b/CPlusPlus20ForProgrammers-master/examples/ch06/a.out differ
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_12.cpp b/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_12.cpp
index 03679c8..2aa0a8f 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_12.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_12.cpp
@@ -29,6 +29,16 @@ T integrate (std::array<T, N> x, F f){
 }
 
 
+auto integrate_auto (auto x, auto f){
+        auto tmp{x[0]};
+	tmp = 0.0;
+        for (auto s: x){
+            tmp+= f(s);
+        }
+        return tmp;
+}
+
+
 typedef double (*FUNC)(double&);
 
 
@@ -71,6 +81,8 @@ int main() {
 
    std::cout << "Integration  full  template  " << integrate(floats, f_lambda) << "\n";
 
+   std::cout << "Integration  auto          " << integrate_auto(floats, f_lambda) << "\n";
+
    std::cout << "Lambda test   " << g_lambda(floats) << "\n";
 }
 
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch07/a.out b/CPlusPlus20ForProgrammers-master/examples/ch07/a.out
index a6107a0..9f27eb8 100755
Binary files a/CPlusPlus20ForProgrammers-master/examples/ch07/a.out and b/CPlusPlus20ForProgrammers-master/examples/ch07/a.out differ
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_01.cpp b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_01.cpp
index ae220a6..5914c99 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_01.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_01.cpp
@@ -2,6 +2,7 @@
 // Pointer operators & and *.
 #include <iostream>
 #include <array>
+#include <memory>
 using namespace std;
 
 int main() {
@@ -12,6 +13,9 @@ int main() {
       << "\nThe value of aPtr is " << aPtr;
    cout << "\n\nThe value of a is " << a
       << "\nThe value of *aPtr is " << *aPtr << '\n';
+
+   std::shared_ptr < std::array<int,10> > b = std::make_shared< std::array<int,10> > ();
+   std::cout << (*b)[3] << " " << b->at(5) <<"\n";
 }
 
 
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_03.cpp b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_03.cpp
index a2e2fc7..f24a542 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_03.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_03.cpp
@@ -1,24 +1,49 @@
 // fig07_03.cpp
 // Pass-by-reference with a pointer argument used to cube a 
 // variable's value.
-#include <fmt/format.h>
 #include <iostream>
 
-void cubeByReference(int* nPtr); // prototype 
+void cubeByValue(int x);
+void cubeByReference(int& x); // prototype 
+void cubeByPointer(int* nPtr);
 
 int main() {
    int number{5};
    std::cout << "Original value of number is " << number << "\n";
-   cubeByValue(number); // pass number by value to cubeByValue
+   cubeByPointer(&number); // pass number by value to cubeByValue
    std::cout << "New value of number is " << number <<"\n";
 
+   int number1{5};
+   
+   std::cout << "Original value of number is " << number1 << "\n";
+   cubeByReference(number1); // pass number by value to cubeByValue
+   std::cout << "New value of number is " << number1 <<"\n";
+
+
+   int number2{5};
+    std::cout << "Original value of number is " << number2 << "\n";
+   cubeByValue(number2); // pass number by value to cubeByValue
+   std::cout << "New value of number is " << number2 <<"\n";
+
+
+   
+
 }
 
 // calculate cube of *nPtr; modifies variable number in main 
-void cubeByReference(int* nPtr) {
+void cubeByPointer(int* nPtr) {
    *nPtr = *nPtr * *nPtr * *nPtr; // cube *nPtr              
 }
 
+void cubeByValue(int x) {
+   x = x * x * x; // cube *nPtr
+}
+
+void cubeByReference(int& x) {
+   x = x * x * x; // cube *nPtr
+}
+
+
 /**************************************************************************
  * (C) Copyright 1992-2022 by Deitel & Associates, Inc. and               *
  * Pearson Education, Inc. All Rights Reserved.                           *
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_06.cpp b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_06.cpp
index 51537d7..eb5941f 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_06.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_06.cpp
@@ -1,6 +1,5 @@
 // fig07_06.cpp
 // C++20: Creating std::arrays with to_array.
-#include <fmt/format.h>
 #include <iostream>
 #include <array>
 
@@ -9,8 +8,9 @@ int main() {
    const auto display{
       [](const auto& items) {
          for (const auto& item : items) {
-            std::cout << fmt::format("{} ", item);
+            std::cout << item << " ";
          }
+	 std::cout << "\n";
       }
    };
 
@@ -19,14 +19,12 @@ int main() {
    // creating a std::array from a built-in array
    const auto array1{std::to_array(values1)};
 
-   std::cout << fmt::format("array1.size() = {}\n", array1.size())
-      << "array1: ";
+   std::cout << "array1.size(): " << array1.size()  << " array1: ";
    display(array1); // use lambda to display contents
 
    // creating a std::array from an initializer list
    const auto array2{std::to_array({1, 2, 3, 4})};
-   std::cout << fmt::format("\n\narray2.size() = {}\n", array2.size())
-      << "array2: ";
+   std::cout << "array2.size(): " << array2.size()  << " array2: ";
    display(array2); // use lambda to display contents
 
    std::cout << '\n';
diff --git a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_10.cpp b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_10.cpp
index f7e8d42..23b666c 100644
--- a/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_10.cpp
+++ b/CPlusPlus20ForProgrammers-master/examples/ch07/fig07_10.cpp
@@ -2,19 +2,38 @@
 // Sizeof operator when used on a built-in array's name
 // returns the number of bytes in the built-in array.
 #include <iostream>
+#include <span>
 
 size_t getSize(double* ptr); // prototype
+size_t getSize_span(std::span<double> ptr);
+
+void print_arr(auto a){
+        for (auto x: a)
+                std::cout << x << " ";
+}
+
+void fill_arr(auto& a){
+        for (auto x: a)
+                x = 0;
+}
+
 
 int main() {
    double numbers[20]; // 20 doubles; occupies 160 bytes on our system
 
+   auto numbers_span {std::span<double>(numbers)};
+   fill_arr(numbers_span);
 
 
    std::cout << "Number of bytes in numbers is " << sizeof(numbers)<<"\n";
 
-   std::cout << "Actual nukber of elements : " << sizeof(numbers)/sizeof(double) << "\n";
+   std::cout << "Actual number of elements : " << sizeof(numbers)/sizeof(double) << "\n";
 
    std::cout << "Number of bytes returned by getSize is " <<     getSize(numbers) << "\n";
+
+   std::cout << "Actual number of elements returned by getSize_span is " <<     getSize_span(numbers) << "\n";
+
+   print_arr(numbers_span);
 }
 
 // return size of ptr         
@@ -22,6 +41,11 @@ size_t getSize(double* ptr) {
    return sizeof(ptr);
 }
 
+size_t getSize_span(std::span<double> ptr) {
+   return ptr.size();
+}
+
+
 
 
 /**************************************************************************