ch3_cpp_basic.cpp

#include <iostream>
// The slight difference between c an c++

int main()
{
    // section 1: input and output using c++ cin and cout

    // in c, input and output is scanf and printf
    std::cout << "Wellcome to c++ HELL!!\nInput your unlucky number:";
    int num = 0;
    std::cin >> num;
    std::cout << "Your unlucky number is: " << num << "\n";

    std::cout << std::endl;

    // section 2: string

    // string is char[] with additional function on top of it

    std::string lowercase_str = "meow";

    std::cout << "upper_str: " << lowercase_str << "\n";

    // to upper case
    for (int i = 0; i < lowercase_str.size(); i++)
    {
        lowercase_str[i] = lowercase_str[i] - ('a' - 'A'); // ascii code!
    }

    std::cout << "upper case string: " << lowercase_str << "\n";

    std::string str = "Do weebs in ICAL has boyfriend/girlfriend?";
    std::string str2("girlfriend");

    int found = str.find(str2);

    if (found == std::string::npos) // if not fond
    {
        std::cout << "String not found!\n"
                  << "The program now dies!!!\n";

        exit(-1);
    }
    std::cout << "found at " << found << "\n";

    // section 3 and section 4 is c not c++

    // section 3: 1d array

    int arr[9] = {0}; // all 0

    for (int i = 0; i < 9; i++)
    {
        std::cout << arr[i] << " ";
    }
    std::cout << "\n";

    // section 4: 2d array

    int arr2d[3][4] = {{0, 1, 2, 3}, {4, 5, 6, 7}, {8, 9, 10, 11}};

    for (int i = 0; i < 3; i++)
    {
        for (int j = 0; j < 4; j++)
        {
            std::cout << arr2d[i][j] << " ";
        }
        std::cout << "\n";
    }

    return 0;
}