Таблицы с прямой адресацией

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
vector<string> vec;
const int SIZE = 5;
 
void init() {
    vec.reserve(SIZE);
    string s = "test";
    for (size_t i = 0; i < SIZE; ++i) {
        vec.push_back(s);
        s += "0";
    }
}
double  result[SIZE] = {
    0.0, 1.0, 2.0, 3.0, 4.0
};
 
double directAddressSearch(double *result, int key) {
    return result[key];
}
 
void directAddressInsert(double * result, int key, double newVal) {
    result[key] = newVal;
}
void directAddressDelete(double * result, int key) {
    result[key] = NULL;
}
int getIndex(std::string const &  str) {
    for (int i = 0; i < vec.size(); ++i) {
        if (vec[i] == str) {
            return i;
        }
    }
    return -1; 
}
 
int _tmain(int argc, _TCHAR* argv[])
{
    init();
    string str = "test00";
    std::cout << "test Get By Name : \n" << directAddressSearch(result, getIndex(str)) << std::endl;
    directAddressInsert(result, getIndex(str), 645.34);
    std::cout << "test Get By Name After change value : \n" << directAddressSearch(result, getIndex(str)) << std::endl;
 
    return 0;
}