C++23 brought a new and useful addition to the language: insert_range().
This new member function provides a more efficient way to insert a range of elements into a vector. Until C++23, the only way to insert a range of elements into a vector was to use a loop. For example:
std::vector<int> vec1 = {1, 2, 3, 4, 5};
std::vector<int> vec2 = {6, 7, 8, 9, 10};
for (int i = 0; i < vec2.size(); i++)
{
vec1.insert(vec1.begin() + 2 + i, vec2[i]);
}
// Print the vector
for (int i = 0; i < vec1.size(); i++)
{
std::cout << vec1[i] << ” “;
}
Our output will be: 1 2 6 7 8 9 10 3 4 5
However, especially when we use large vectors, loops could be very inefficient. When you loop through a large container, you are essentially accessing each element in the container one at a time. This can be a very slow process, especially if the container is very large.
The insert_range() function solves this problem by providing a single function that can be used to insert a range of elements into a vector with a single function call. So now, instead of using the loop in our previous code, we can simply write:
std::vector<int> vec1 = {1, 2, 3, 4, 5};
std::vector<int> vec2 = {6, 7, 8, 9, 10};
auto iter = vec1.insert_range(vec1.begin() + 2, vec2.begin(), vec2.end());
for (int i = 0; i < vec1.size(); i++)
{
std::cout << vec1[i] << ” “;
}
As you can see, we don’t need to use a loop, we simply add the new range to our vector.
The new insert_range() function is a really valuable addition to the C++ language, and we expect it will be widely used.
In our new book Learning C++ published by Manning Publication, we teach C++ core language features, including the newest C++23 standard.
|",
"|_______|"},
{" _______ ", "|2 |", "| _ |", "| |_) |", "| / |",
"|_______|"},
{" _______ ", "|3 |", "| __ |", "| |_ \\|", "|____/\\|",
"|_______|"},
{" _______ ", "|4 |", "| |_ _||", "| | |", "| | |",
"|_______|"},
{" _______ ", "|5 |", "| |__ |", "| | |", "| |__| |",
"|_______|"},
{" _______ ", "|6 |", "| |__ |", "| |__| |", "| |__| |",
"|_______|"},
{" _______ ", "|7 |", "| |___ |", "| / /|", "| / / |",
"|_______|"},
{" _______ ", "|8 |", "| /\\ |", "| / \\ |", "| \\ / |",
"|_______|"},
{" _______ ", "|9 |", "| /\\ |", "| |__| |", "| / |",
"|_______|"},
{" _______ ", "|10 |", "| /\\ |", "| |__) |", "|____ |",
"|_______|"},
{" _______ ", "|J |", "| /\\|", "| / / |", "| / / |",
"|_/_____|"},
{" _______ ", "|Q |", "| /\\|", "| / \|", "| |\\__|",
"|_/_____|"},
{" _______ ", "|K |", "| \\_/|", "| / \\|", "| | \|",
"|_/_____|"}};
std::random_device rd;
std::mt19937 rng(rd());
std::shuffle(images.begin(), images.end(), rng);
std::vector<std::string> selectedImages;
int randomIndex = rand() % images.size();
const std::vector<std::string>& image = images[randomIndex];
for (const std::string& line : image)
{
selectedImages.push_back(line);
}
images.erase(images.begin() + randomIndex);
return selectedImages;
}
std::vector<std::vector<Pixel>>
composeCombinedImage(const std::vector<std::string>& image1,
const std::vector<std::string>& image2,
const std::vector<std::string>& image3, Color color1,
Color color2, Color color3)
{
// #B
int maxLines = std::max({image1.size(), image2.size(), image3.size()});
// #C
int maxWidth =
std::max({image1[0].size(), image2[0].size(), image3[0].size()});
std::vector<std::vector<Pixel>> combinedImage(maxLines);
// #D
for (int i = 0; i < image1.size(); ++i)
{
for (char c : image1[i])
{
combinedImage[i].push_back({c, color1});
}
// #E
int spacesToAdd = maxWidth - image1[i].size();
for (int j = 0; j < spacesToAdd; ++j)
{
combinedImage[i].push_back({' ', Color::DEFAULT});
}
}
// #F
for (int i = image1.size(); i < maxLines; ++i)
{
for (int j = 0; j < maxWidth; ++j)
{
combinedImage[i].push_back({' ', Color::DEFAULT});
}
}
// #G
for (int i = 0; i < image2.size(); ++i)
{
for (char c : image2[i])
{
combinedImage[i].push_back({c, color2});
}
// #H
int spacesToAdd = maxWidth - image2[i].size();
for (int j = 0; j < spacesToAdd; ++j)
{
combinedImage[i].push_back({' ', Color::DEFAULT});
}
}
// #I
for (int i = image2.size(); i < maxLines; ++i)
{
for (int j = 0; j < maxWidth; ++j)
{
combinedImage[i].push_back({' ', Color::DEFAULT});
}
}
// #J
for (int i = 0; i < image3.size(); ++i)
{
for (char c : image3[i])
{
combinedImage[i].push_back({c, color3});
}
// #K
int spacesToAdd = maxWidth - image3[i].size();
for (int j = 0; j < spacesToAdd; ++j)
{
combinedImage[i].push_back({' ', Color::DEFAULT});
}
}
return combinedImage;
}
bool checkWin(const std::vector<std::string>& image1,
const std::vector<std::string>& image2,
const std::vector<std::string>& image3, Color color1,
Color color2, Color color3)
{
return (image1 == image2 && image2 == image3 && color1 == color2 &&
color2 == color3);
}
int main()
{
srand(static_cast<unsigned>(time(0)));
std::cout << "Welcome to the Slot Machine Game!" << std::endl;
std::cout << "Press any key to start..." << std::endl;
while (true)
{
_getch();
CLEAR_SCREEN;
// #L
std::vector<std::string> image1 = generateRandomImage();
std::vector<std::string> image2 = generateRandomImage();
std::vector<std::string> image3 = generateRandomImage();
// #M
Color color1 =
static_cast<Color>(rand() % static_cast<int>(Color::CYAN) + 1);
Color color2 =
static_cast<Color>(rand() % static_cast<int>(Color::CYAN) + 1);
Color color3 =
static_cast<Color>(rand() % static_cast<int>(Color::CYAN) + 1);
// #N
std::vector<std::vector<Pixel>> combinedImage = composeCombinedImage(
image1, image2, image3, color1, color2, color3);
// #O
displayMatrix(combinedImage);
// #P
if (checkWin(image1, image2, image3, color1, color2, color3))
{
std::cout << "Congratulations! You win!" << std::endl;
}
else
{
std::cout << "Sorry, better luck next time!" << std::endl;
}
std::cout << std::endl;
}
return 0;
}
Learning C++ 