[update] pointer

.github/workflows/c-cpp.yml

@@ -1,30 +1,29 @@
-name: C/C++ CI
+# name: C/C++ CI
 
-on:
-  push:
-    branches:
-      - main  # Modify this to match your main branch name
-  pull_request:
-    branches:
-      - main  # Modify this to match your main branch name
+# on:
+#   push:
+#     branches:
+#       - main  # Modify this to match your main branch name
+#   pull_request:
+#     branches:
+#       - main  # Modify this to match your main branch name
 
-jobs:
-  build:
-    runs-on: ubuntu-latest
+# jobs:
+#   build:
+#     runs-on: ubuntu-latest
 
-    steps:
-    - name: Checkout code
-      uses: actions/checkout@v2
-
-    - name: Set up CMake
-      uses: cmake/setup-cmake@v1
+#     steps:
+#     - name: Checkout code
+#       uses: actions/checkout@v2
 
-    - name: Configure CMake
-      run: cmake -Bbuild -S.
+#     - name: Set up CMake
+#       uses: cmake/setup-cmake@v1
 
-    - name: Build
-      run: cmake --build build
+#     - name: Configure CMake
+#       run: cmake -Bbuild -S.
 
-    - name: Run tests
-      run: cd build && ctest --output-on-failure
+#     - name: Build
+#       run: cmake --build build
 
+#     - name: Run tests
+#       run: cd build && ctest --output-on-failure

Introduction/pointer/Basic/Pointer.cpp

@@ -0,0 +1,32 @@
+/*
+*
+* Basic explanation:
+* A pointer is a variable that stores the memory address of another variable.
+* Pointers are used for various purposes, including dynamic memory allocation, arrays, and functions.
+*
+*/
+
+#include <iostream>
+
+int main(){
+  int var = 42;
+  int* ptr = &var;
+
+ // Output the value of var
+  std::cout << "Value of var: " << var << std::endl;
+   // Output the address of var
+  std::cout << "Address of var: " << &var << std::endl;
+  // Output the address of ptr
+  std::cout << "Address of ptr: " << &ptr << std::endl;
+  // Output the address stored in ptr
+  std::cout << "Value stored in ptr: " << ptr << std::endl;
+  // Output the value pointed to by ptr
+  std::cout << "Value pointed to by ptr: " << *ptr << std::endl;
+
+  *ptr = 50;
+
+  //Output the new value of var
+  std::cout << "New value of var: " << var << std::endl;
+
+  return 0;
+}

Introduction/pointer/Exercises/PointerArithmetic.cpp

@@ -0,0 +1,45 @@
+/**
+ * @file PointerArithmetic.cpp
+ * @author your name (you@domain.com)
+ * @brief
+ * @version 0.1
+ * @date 2024-05-22
+ *
+ * @copyright Copyright (c) 2024
+ *
+ * Write a program that uses pointer arithmetic to iterate over an array of integers and print out each element.
+ */
+
+#include <iostream>
+#include <iterator>
+
+using namespace std;
+
+/**
+ * total_size_of_arr = number_of_elements * size_of_each_element
+                  = 5 * sizeof(int)
+                  = 5 * 4
+                  = 20 bytes
+ * sizeof(arr) = 20
+ * 1 byte = 8 bit
+ * int = 4byte | char = 1byte | string usually implemented as a dynamic array
+ * The & operator (address of the operator) is placed before the variable name and knows the address of the first memory cell in the memory area of that variable.
+ * The * operator (referencing operator or indirection operator) is placed before an address to retrieve the value stored at that address.
+ * *&a ~ a
+ * <data_type> *<pointer_variable_name>;
+ * void *p;
+ */
+
+int main(int argc, char **argv){
+  int arr[] = {1,2,3,4,5};
+
+  int* beginPtr = begin(arr);
+  int* endPtr = end(arr);
+
+  for (int* ptr = beginPtr; ptr != endPtr; ++ptr)
+  {
+    cout << "Element " << *ptr << endl;
+  }
+
+  return 0;
+}

Introduction/pointer/Exercises/README.md

@@ -0,0 +1,29 @@
+Simple Pointer Declaration and Usage:
+Declare a pointer variable to an integer, assign it the address of an integer variable, and then print the value of the variable through the pointer.
+
+Pointer Arithmetic:
+Write a program that uses pointer arithmetic to iterate over an array of integers and print out each element.
+
+Pointer to Pointer:
+Declare a pointer to a pointer to an integer. Allocate memory for an integer, assign its address to the first pointer, and then assign the address of the first pointer to the second pointer. Print out the value of the integer using both pointers.
+
+Dynamic Memory Allocation:
+Write a program that dynamically allocates an array of integers of size n (input from the user), initializes the elements, and then prints them out using pointer notation.
+
+Swap Function with Pointers:
+Write a function that swaps the values of two integers using pointers. Test the function in the main program.
+
+Passing Pointers to Functions:
+Write a function that takes an array of integers and its size as arguments and returns the sum of all elements. Use pointers to access array elements within the function.
+
+Pointer to Function:
+Define a function that accepts a pointer to another function as an argument. Use this function to call different functions based on the pointer passed.
+
+Pointer to Constant Data:
+Declare a constant integer variable and a pointer to a constant integer variable. Try to change the value of the constant integer through the pointer. Repeat the process with a pointer to a constant pointer.
+
+Dynamic Memory Allocation for 2D Arrays:
+Write a program that dynamically allocates memory for a 2D array of integers of size m x n (input from the user), initializes the elements, and then prints them out using pointer notation.
+
+Linked List Implementation:
+Implement a simple linked list data structure in C++. Define a Node structure with an integer data field and a pointer to the next Node. Write functions to insert elements at the beginning and end of the list, delete elements, and print the list.

Introduction/pointer/Exercises/SimplePointer.cpp

@@ -0,0 +1,25 @@
+/**
+ * @file SimplePointer.cpp
+ * @author your name (you@domain.com)
+ * @brief
+ * @version 0.1
+ * @date 2024-05-22
+ *
+ * @copyright Copyright (c) 2024
+ *
+ * Declare a pointer variable to an integer, assign it the address of an integer variable, and then print the value of the variable through the pointer.
+ */
+
+#include <iostream>
+
+int main() {
+    int var = 10;
+    int* ptr = &var;
+
+    std::cout << "Original value of var: " << var << std::endl;
+
+    *ptr = 20;
+    std::cout << "Modified value of var: " << var << std::endl;
+
+    return 0;
+}