commit 014b381086a2075c75cbfc42b41d3d953041df13
Author: Harun Teper <harun.teper@tu-dortmund.de>
Date:   Wed Jun 24 16:08:11 2020 +0200

    first hashtable implementation

diff --git a/HashTabelle.h b/HashTabelle.h
new file mode 100644
index 0000000..424b73c
--- /dev/null
+++ b/HashTabelle.h
@@ -0,0 +1,151 @@
+#pragma once
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <mutex>
+#include <taskflow/taskflow.hpp>
+
+template<typename T>
+class HashTable {
+public:
+    struct elem {
+    public:
+        T* data;
+        int key;
+    };
+    struct hashList {
+    public:
+        std::vector<elem> list;
+    };
+
+    int size;
+    int elements;
+    std::vector<hashList> table;
+
+    HashTable(int size);
+    ~HashTable();
+
+    void insert(int id, T* n);
+    bool search(int id);
+    bool remove(int id);
+
+    void restructure();
+
+    int getSize();
+    int getElements();
+    double getUtilization();
+
+    void print();
+
+    int hash(int id);
+
+private:
+};
+
+template < typename T >
+HashTable<T>::HashTable(int size) {
+    this->size = size;
+    this->table = std::vector<hashList>(size);
+};
+
+template < typename T >
+HashTable<T>::~HashTable() {
+    //table.clear();
+    //table.shrink_to_fit();
+    std::vector<hashList>().swap(table);
+}
+
+template < typename T >
+int HashTable<T>::getSize() {
+    return size;
+}
+
+template < typename T >
+int HashTable<T>::getElements() {
+    return elements;
+}
+
+template < typename T >
+double HashTable<T>::getUtilization() {
+    return (double)elements/size;
+}
+
+template < typename T >
+int HashTable<T>::hash(int id) {
+    return id % size;
+}
+
+template < typename T >
+bool HashTable<T>::search(int id) {
+    int index = hash(id);
+    std::vector<elem> list = table.at(index).list;
+    for (auto it = list.begin(); it != list.end(); ++it) {
+        if (it->key == id) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+template < typename T >
+void HashTable<T>::insert(int id, T* data) {
+    int index = hash(id);
+    if (search(id)){
+        std::vector<elem> list = table[index].list;
+        for (auto it = table[index].list.begin(); it != table[index].list.end(); ++it) {
+            if (it->key == id) {
+                it->data = data;
+            }
+        }
+    }
+    else{
+        table[index].list.push_back(elem{ data, id });
+        elements++;
+    }
+}
+
+template < typename T >
+bool HashTable<T>::remove(int id) {
+    int index = hash(id);
+    std::vector<elem> list = table[index].list;
+    int elemindex = 0;
+
+    for (auto it = table[index].list.begin(); it != table[index].list.end(); ++it) {
+        if (it->key == id){
+            table[index].list.erase(table[index].list.begin() + elemindex);
+            elements--;
+            return true;
+        }
+        elemindex++;
+    }
+    return false;
+}
+
+template < typename T >
+void HashTable<T>::print() {
+
+    for (auto it = table.begin(); it != table.end(); ++it) {
+        std::cout << "Next list" << std::endl;
+        for (auto it2 = it->list.begin(); it2 != it->list.end(); ++it2) {
+            std::cout << it2->data << std::endl;
+        }
+    }
+
+}
+
+template < typename T >
+void HashTable<T>::restructure() {
+
+    std::vector<hashList>oldTable = table;
+
+    size = size * 2;
+    table = std::vector<hashList>(size);
+
+    for (auto it = oldTable.begin(); it != oldTable.end(); ++it) {
+        for (auto it2 = it->list.begin(); it2 != it->list.end(); ++it2) {
+            insert(it2->key, it2->data);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Quelle.cpp b/Quelle.cpp
new file mode 100644
index 0000000..1ab493c
--- /dev/null
+++ b/Quelle.cpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include "HashTabelle.h"
+#include <iostream>
+#include <string>
+#include <taskflow/taskflow.hpp>
+
+using namespace std;
+
+struct Customer {
+    int id;
+    string vorname;
+    string nachname;
+
+    friend ostream& operator<<(ostream& os, const Customer& c) {
+        os << "Id: " << c.id << "\n" << "Vorname: " << c.vorname << "\n" << "Nachname: " << c.nachname << "\n";
+        return os;
+    }
+};
+
+int main() {
+    Customer c{ 20, "Max", "Mustermann" };
+    Customer d{ 30, "Tom", "Mot" };
+
+
+    HashTable<Customer> table = HashTable<Customer>(10);
+
+    table.insert(20, &c);
+    table.insert(30, &c);
+    table.insert(21, &c);
+    table.insert(21, &d);
+
+    std::cout << table.search(30) << std::endl;
+
+    table.remove(30);
+
+    std::cout << table.search(30) << std::endl;
+
+    table.remove(40);
+
+    table.restructure();
+
+    table.print();
+}