pointersLectureBBR192

#include <iostream>

void swapVal(int& a, int& b)
{
    int tmp{};
    std::cout << "a = " << a << " b= " << b << '\n';
    tmp = a;
    a = b;
    b = tmp;
    std::cout << "a = " << a << " b= " << b << '\n';
}

void swapValPtr(int* a, int* b)
{
    int tmp{};
    std::cout << "a = " << *a << " b= " << *b << '\n';
    tmp = *a;
    *a = *b;
    *b = tmp;
    std::cout << "a = " << *a << " b= " << *b << '\n';
}

int& maxArr(int* arr, int size)
{
    int maxIdx{ 0 };
    for (int i{ 0 }; i < size; ++i)
    {
        maxIdx = arr[maxIdx] > arr[i] ? maxIdx: i;
    }
    return arr[maxIdx];
}

int main()
{
    int x{ 10 };
    int y{ 20 };
    int* const ptrX{ &x };
    int& refX{ x };

    int arr[5]{ 10,30,67,1,4 };

    std::cout << arr[2] << '\n';

    maxArr(arr, 5) += 100;

    std::cout <<  arr[2] << '\n';

    //int* ptrX{ &x };
    //int* ptrY{ &y };

    //std::cout << "x = " << x << " y= " << y << '\n';
    //swapVal(x, y);
    //std::cout << "x = " << x << " y= " << y << '\n';

    //std::cout << "x = " << x << " y= " << y << '\n';
    //std::cout <<  << '\n';
}


#include <iostream>

void swapVal(int a, int b)
{
    int tmp{};
    std::cout << "a = " << a << " b= " << b << '\n';
    tmp = a;
    a = b;
    b = tmp;
    std::cout << "a = " << a << " b= " << b << '\n';
}

void swapValPtr(int* a, int* b)
{
    int tmp{};
    std::cout << "a = " << *a << " b= " << *b << '\n';
    tmp = *a;
    *a = *b;
    *b = tmp;
    std::cout << "a = " << *a << " b= " << *b << '\n';
}

int* foo()
{
    int bad{ 33 };
    return &bad;
}

void boo()
{
    int arr[1000]{};
}

int main()
{
    int* ptr = foo();
    std::cout << *ptr << '\n';
    boo();


    int x{ 10 };
    int y{ 20 };

    //int* ptrX{ &x };
    //int* ptrY{ &y };

    std::cout << "x = " << x << " y= " << y << '\n';
    swapValPtr(&x, &y);
    std::cout << "x = " << x << " y= " << y << '\n';

}




#include <iostream>

int* createArr(int size)
{
    return new int[size];
}

void deleteArr(int* ptr)
{
    delete[] ptr;
}

void fillArr(int* ptr, int size)
{
    for (auto elP{ ptr }; elP != (ptr + size); *elP++ = rand() % 30);
}

void printArr(int* ptr, int size)
{
    for (auto elP{ ptr }; elP != (ptr + size); ++elP)
    {
        std::cout << *elP << ' ';
    }
    std::cout << '\n';
}

int main()
{
    int size{};
    std::cout << "Enter array size\n";
    std::cin >> size;

    int size1{};
    std::cout << "Enter array1 size\n";
    std::cin >> size1;

    int* ptr = createArr(size);
    fillArr(ptr, size);
    int* ptr1 = createArr(size1);
    fillArr(ptr1, size1);

    printArr(ptr, size);
    printArr(ptr1, size1);

    deleteArr(ptr);
    deleteArr(ptr1);

    int arr[5]{ 20,45,67,8,1 };
    printArr(arr, 5);
    fillArr(arr, 5);
    printArr(arr, 5);


    //int* ptr{ new int[size] {} };
    //int* const begin{ ptr };
    //int* const end{ ptr + size };

    //for (; ptr != end; ++ptr)
    //{
    //  std::cout << (*ptr = rand() % 30) << ' ';
    //}
    //std::cout << '\n';

    //delete[] begin;

    //const int arrSize{ 10 };
    //int arr[arrSize]{ 1,2,3,4,5,6,7,8,9,10 };///100[1]... 136[10] 140
    //int tmp{};
    ////for (int head{0}, tail{ arrSize - 1 }; head < tail; ++head, --tail)
    ////{
    ////    tmp = *(arr + head);
    ////    *(arr + head) = *(arr+tail);
    ////    *(arr+tail) = tmp;
    ////}
    //int* begin{ arr };
    //int* end{ arr + arrSize - 1 };

    //while (begin < end)
    //{
    //  tmp = *begin;
    //  *begin = *end;
    //  *end = tmp;
    //  ++begin;
    //  --end;
    //}


    //for (auto elP{ arr }; elP != (arr + arrSize); ++elP)
    //{
    //  std::cout << *elP << ' ';
    //}
    //std::cout << '\n';


    //int* ptr{ arr + arrSize - 1 };

    //std::cout << &arr[0] << " <==> " << arr << " <==> " << ptr << '\n';
    //
    //for (; ptr != (arr + arrSize); ++ptr)
    //{
    //  std::cout << *ptr << ' ';
    //}
    //std::cout << '\n';
    //std::cout << *ptr << ' ';
}

//ctrl + K + C
//ctrl + K + U
//int num{ 65535 };
//for (int i{ 0 }; i < 4; ++i)
//{
//  std::cout << (int)*((uint8_t*)&num + i) << '\n';
//}

//A[N]{ 1,1,3,5,8,3,9,0,3 }
//B[M]{ 2,2,4,2,7,9,0,1,4 }
//C[3]{ 3,5,8 }
//D[]{ 3,5,8 }
//
//A[N]{ 0,1,1,3,3,3,5,8,9 }
//B[M]{ 0,1,2,2,2,4,4,7,9 }
//
//AU[NU]{ 0,1,3,5,8,9 }
//BU[MU]{ 0,1,2,4,7,9 }
//
//C[NU]{ 3,5,8 }
//CR[3]{ 3,5,8 }