Getting data from two different arrays for the same index - c++

Question

I created an array like this:
string mobs [5] = {"Skeleton", "Dragon", "Imp", "Demon", "Vampire"};
int mobHP[5] = {10, 11, 12, 13, 14, 15};
I created a random number generator for getting the mob number that i want, but I failed. Supposing, the generated number is 4, how will I equate or equalize it to string mob number 5, and mob hp number 5?

Answer 1

If you have a function that returns a random number between 0 and 4 (Array Indexes) then the code would look something like:
// Since we are using raw arrays we need to store the length
int array_length = 5
// Some function that returns a random number between
int randomIndex = myRandomNumberFunction(array_length)
// Now we select from the array using the index we calculated before
std::string selectedMobName = mobs[randomIndex]
int selectMobHP = mobHP[randomIndex]
However a better way to achieve this using modern C++ practices would be to create a monster class and use it in a vector like so:
#include <vector>
#include <string>
#include <iostream>
// Normally we would use a class with accessors here but for the sake
// of brevity and simplicity we'll use a struct
struct Monster {
Monster(const std::string& in_name, const int in_health) :
name(in_name), health(in_health)
{}
std::string name;
int health;
};
// A vector is like an array that can grow larger if you add stuff to it
// Note: Normally we wouldn't use a raw pointer here but I've used it for
// for the sake of brevity. Instead we would either use a smart pointer
// or we would implement the Monster class with a copy or move constructor.
std::vector<Monster*> monsters;
monsters.push_back(new Monster("Dragon", 5));
monsters.push_back(new Monster("Eelie", 3));
... // Arbitrary number of monsters
monsters.push_back(new Monster("Slime", 1));
// Select a random monster from the array
int random_index = myRandomNumberFunction(monsters.size());
Monster* selected_monster = monsters[random_index];
// Print the monster stats
std::cout << "You encounter " << selected_monster->name << " with "
<< selected_monster->health << "hp" << std::endl;
// Clean up the vector since we're using pointers
// If we were using smart pointers this would be unnecessary.
for(std::vector<Monster*>::iterator monster = monsters.begin();
monster != monsters.end();
++monster) {
delete (*monster);
}

Answer 2

For an array of N elements, the valid indices are in the range of 0 to N-1, where 0 denotes the first element and N-1 denotes the last element.
As you have a generated number in this range, it maps directly onto the elements of the arrays.
If you have the value ix=4, it refers to the fifth monster. You access the name at mobs[ix] and the health at mobHP[ix].