A. In C++ implement std::map without using STL

B. Write a for loop that takes an input from the user to add up the numbers from 1 to the specified number. (Provide the script and the output)

Sol12:

A. Implementing std::map without using the STL involves creating your own associative container that stores elements as key-value pairs. Here\'s an example implementation in C++:

scssCopy code#include #include // for std::pair template class Map { private: struct Node { Key key; Value value; Node* left; Node* right; Node(Key k, Value v) : key(k), value(v), left(nullptr), right(nullptr) {} }; Node* root; public: Map() : root(nullptr) {} void insert(Key key, Value value) { Node** cur = &root; while (*cur != nullptr) { if (key key) { cur = &((*cur)->left); } else { cur = &((*cur)->right); } } *cur = new Node(key, value); } Value& operator[](Key key) { Node** cur = &root; while (*cur != nullptr) { if (key key) { cur = &((*cur)->left); } else if (key > (*cur)->key) { cur = &((*cur)->right); } else { return (*cur)->value; } } *cur = new Node(key, Value()); return (*cur)->value; } bool contains(Key key) { Node* cur = root; while (cur != nullptr) { if (key key) { cur = cur->left; } else if (key > cur->key) { cur = cur->right; } else { return true; } } return false; } };

This implementation uses a binary search tree to store the key-value pairs, with the keys determining the position of each element in the tree. The insert method adds a new element to the tree, while the operator[] method retrieves the value associated with a given key (and inserts a new element with a default-constructed value if the key doesn\'t already exist). The contains method checks if a given key exists in the tree.

B. Here\'s an example C++ for loop that takes an input from the user and adds up the numbers from 1 to the specified number:

cCopy code#include int main() { int n; std::cout \"Enter a number: \"; std::cin >> n; int sum = 0; for (int i = 1; i =>std::cout \"The sum of the numbers from 1 to \" \" is \" std::endl; return 0; }

This code prompts the user to enter a number, then uses a for loop to add up the numbers from 1 to that number. The resulting sum is printed to the console. Here\'s an example output for the input 5:

pythonCopy codeEnter a number: 5 The sum of the numbers from 1 to 5 is 15