diff --git a/Workbook/Makefile b/Workbook/Makefile
new file mode 100644
index 0000000..bf84aa3
--- /dev/null
+++ b/Workbook/Makefile
@@ -0,0 +1,36 @@
+##
+# TH WWS
+#
+# @file
+# @version 0.1
+CC = gcc
+CFLAGS ?= -Wall -Wextra -Iinclude -fomit-frame-pointer -O2
+
+SRC_DIR = src
+INCLUDE_DIR = include
+BUILD_DIR = build
+TARGET = WWS_System
+
+SRC_FILES = $(wildcard $(SRC_DIR)/*.c)
+OBJ_FILES = $(patsubst $(SRC_DIR)/%.c, $(BUILD_DIR)/%.o, $(SRC_FILES))
+
+.PHONY: all clean
+
+all: $(BUILD_DIR) $(TARGET)
+
+# Link all the files into the final executable
+$(TARGET): $(OBJ_FILES)
+	$(CC) $(OBJ_FILES) -o $@
+
+# Compile source- and object files
+$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c | $(BUILD_DIR)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+#Ensure the build directory exists
+$(BUILD_DIR):
+	mkdir -p $(BUILD_DIR)
+
+# Clean build and target
+clean:
+	rm -Rf $(BUILD_DIR) $(TARGET)
+# end
diff --git a/Workbook/include/util.h b/Workbook/include/util.h
new file mode 100644
index 0000000..fd9593d
--- /dev/null
+++ b/Workbook/include/util.h
@@ -0,0 +1,20 @@
+#ifndef UTIL_H_
+#define UTIL_H_
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <ctype.h>
+#include <limits.h>
+
+// Magic number to be returned in case something goes wrong. Lets the program know an error occured. This is kind of a hack.
+#define ERRORRETURN 10787253
+
+void null_terminate(char str[]);
+bool is_num(char *str);
+bool is_int(char *str);
+int get_clean_int();
+double get_clean_num();
+bool is_safe(const char* string);
+#endif // UTIL_H_
diff --git a/Workbook/include/wws.h b/Workbook/include/wws.h
new file mode 100644
index 0000000..dd41489
--- /dev/null
+++ b/Workbook/include/wws.h
@@ -0,0 +1,44 @@
+#ifndef WWS_H_
+#define WWS_H_
+
+#include "util.h"
+
+#define ARRSIZE 4096
+#define EXITVAL 15326
+
+typedef struct Product Product;
+typedef struct Customer Customer;
+
+struct Product {
+    int id;
+    char* name;
+    double price;
+    int amount;
+};
+
+struct Customer {
+    char* name;
+    int id;
+    // NOTE: Always NULL-initialize this!!
+    Product* products[ARRSIZE];
+};
+
+// Implementation details
+int read_id();
+char* read_name();
+double read_price();
+int read_amount();
+int find_first_free_index(Customer customer);
+int find_product(Customer customer, int id); // Returns index of product
+int find_customer(int id); // Returns index in the customers array
+
+// Top-Level functions
+int add_product();
+int print_product();
+int add_customer();
+int print_customer();
+int menu();
+
+extern Customer customers[ARRSIZE];
+
+#endif // WWS_H_
diff --git a/Workbook/src/main.c b/Workbook/src/main.c
new file mode 100644
index 0000000..87e35af
--- /dev/null
+++ b/Workbook/src/main.c
@@ -0,0 +1,13 @@
+#include "wws.h"
+
+int main() {
+    Customer customers[ARRSIZE];
+    memset(customers, 0, sizeof(Customer));
+    while(true) {
+        int exitcode = menu();
+        if (exitcode == EXITVAL) {
+            return 0;
+        }
+    }
+    return 0;
+}
diff --git a/Workbook/src/util.c b/Workbook/src/util.c
new file mode 100644
index 0000000..d490830
--- /dev/null
+++ b/Workbook/src/util.c
@@ -0,0 +1,95 @@
+#include "util.h"
+
+bool is_num(char *str) {
+    if (*str == '+' || *str == '-') {
+        str++;
+    }
+    if (*str == '\0') {
+        return false;
+    }
+    while (*str) {
+        if (!isdigit((unsigned char)*str) || !(*str == '.')) {
+            return true;
+        }
+        str++;
+    }
+
+    return false;
+}
+
+bool is_int(char *str) {
+    if (*str == '+' || *str == '-') {
+        str++;
+    }
+    if (*str == '\0') {
+        return false;
+    }
+    while (*str) {
+        if (!isdigit((unsigned char)*str)) {
+            return true;
+        }
+        str++;
+    }
+
+    return true;
+}
+
+double get_clean_num() {
+    char *buffer;
+    size_t bufsize = 0;
+    char *eptr;
+
+    ssize_t input_length = getline(&buffer, &bufsize, stdin);
+    if (input_length == -1) {
+        printf("Fehler beim lesen des inputs.\n");
+        free(buffer);
+        buffer = NULL;
+        return ERRORRETURN;
+    }
+
+    if (is_num(buffer)) {
+        return strtod(buffer, &eptr);
+    }
+
+    printf("Deine Eingabe ist keine Zahl.\n");
+    free(buffer);
+    buffer = NULL;
+    return ERRORRETURN;
+}
+
+int get_clean_int() {
+    char *buffer;
+    size_t bufsize = 0;
+
+    ssize_t input_length = getline(&buffer, &bufsize, stdin);
+    if (input_length == -1) {
+        printf("Fehler beim lesen des inputs.\n");
+        free(buffer);
+        buffer = NULL;
+        return ERRORRETURN;
+    }
+
+    if (is_int(buffer)) {
+        return atoi(buffer);
+    }
+
+    printf("Deine Eingabe ist keine ganze Zahl.\n");
+    free(buffer);
+    buffer = NULL;
+    return ERRORRETURN;
+}
+
+bool is_safe(const char* string) {
+    if (string == NULL) {
+        return false;
+    }
+
+
+    for (size_t i = 0; string[i] != '\0'; ++i) {
+        if (string[i] == '%') {
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/Workbook/src/wws.c b/Workbook/src/wws.c
new file mode 100644
index 0000000..bc5b821
--- /dev/null
+++ b/Workbook/src/wws.c
@@ -0,0 +1,195 @@
+#include "wws.h"
+#include "util.h"
+#include <stdio.h>
+
+int read_id() {
+    printf("Produktnummer: ");
+    int input = get_clean_int();
+    if (input != ERRORRETURN) {return input;}
+    else {
+        printf("Die eingegebene Produktnummer ist keine Zahl.\n");
+        return ERRORRETURN;
+    }
+}
+
+char* read_name() {
+    char* buffer;
+    size_t buffsize = 0;
+    printf("Name: ");
+    ssize_t input_length = getline(&buffer, &buffsize, stdin);
+    if (input_length == -1) {
+        printf("Fehler beim lesen.\n");
+        free(buffer);
+        buffer = NULL;
+    }
+    return buffer;
+}
+
+double read_price() {
+    printf("Preis: ");
+    double price = get_clean_num();
+    if (price == ERRORRETURN) {return ERRORRETURN;}
+    return price;
+}
+
+int read_amount() {
+    printf("Anzahl: ");
+    int amount = get_clean_int();
+    if (amount == ERRORRETURN) {return ERRORRETURN;}
+    return amount;
+}
+
+int find_first_free_index(Customer customer) {
+    for (int i = 0; i < ARRSIZE; i++) {
+        if (customer.products[i] == NULL) {
+            return i;
+        }
+    }
+    printf("Für diesen Kunden können keine weiteren Produkte hinzugefügt werden.\n");
+    return ERRORRETURN;
+}
+
+int find_product(Customer customer, int id) {
+    for (int i = 0; i < ARRSIZE; i++) {
+        if (customer.products[i]->id == id) {return i;}
+    }
+    return ERRORRETURN;
+}
+
+int find_customer(int id) {
+    for (int i = 0; i < ARRSIZE; i++) {
+        if (customers[i].id == id) {return id;}
+    }
+    return ERRORRETURN;
+}
+
+int add_product() {
+    Product* new_product = (Product*) malloc(sizeof(Product));
+    printf("**********************\n");
+    printf("* WWS Produkteingabe *\n");
+    printf("**********************\n");
+    printf("Bitte geben Sie ihre Kundennumer ein: ");
+    int customer_id = get_clean_int();
+    if (customer_id == ERRORRETURN) {return ERRORRETURN;}
+    Customer* customer = &customers[find_customer(customer_id)];
+    new_product->id = read_id();
+    if (new_product->id == ERRORRETURN) {return ERRORRETURN;}
+    if (find_product(*customer, new_product->id)) {
+        printf("Es existiert bereits ein Produkt mit dieser ID.\n");
+        return ERRORRETURN;
+    }
+    new_product->name = read_name();
+    if (!is_safe(new_product->name)) {
+        printf("Der eingegebene Produktname enthält verbotene Zeichen.\n");
+        return ERRORRETURN;
+    }
+    new_product->price = read_price();
+    if (new_product->price == ERRORRETURN) {return ERRORRETURN;}
+    new_product->amount = read_amount();
+    if (new_product->amount == ERRORRETURN) {return ERRORRETURN;}
+    int free_index = find_first_free_index(*customer);
+    if (free_index == ERRORRETURN) {return ERRORRETURN;}
+    customer->products[free_index] = new_product;
+    return 0;
+}
+
+int print_product() {
+    printf("**********************\n");
+    printf("* WWS Produktausgabe *\n");
+    printf("**********************\n");
+    printf("Bitte geben Sie Ihre Kundennummer ein: ");
+    int customer_id = get_clean_int();
+    if (customer_id == ERRORRETURN) {return ERRORRETURN;}
+    printf("Bitte geben Sie die gewünschte Produktnummer ein: ");
+    int product_id = get_clean_int();
+    if (product_id == ERRORRETURN) {return ERRORRETURN;}
+    int product_index = find_product(customers[customer_id], product_id);
+    if (product_index == ERRORRETURN) {
+        printf("Die Produktnummer konnte nicht gefunden werden.\n");
+        return ERRORRETURN;
+    }
+   
+    Product* product = customers[customer_id].products[product_index];
+    printf("Produktnummer: %d\n", product->id);
+    printf("Produktname: %s\n", product->name);
+    printf("Preis: %f\n", product->price);
+    printf("Anzahl: %d\n", product->amount);
+    return 0;
+}
+
+int add_customer() {
+    Customer* new_customer = (Customer*) malloc(sizeof(Customer));
+    if (new_customer == NULL) {
+        printf("Fehler beim Speicher zuweisen");
+        return ERRORRETURN;
+    }
+    printf("*********************\n");
+    printf("* WWS Kundeneingabe *\n");
+    printf("*********************\n");
+    printf("Kundennummer: ");
+    new_customer->id = get_clean_int();
+    if (new_customer->id == ERRORRETURN) {return ERRORRETURN;}
+    printf("Kundenname: ");
+    new_customer->name = read_name();
+    if (!is_safe(new_customer->name)) {
+        printf("Der eigegebene Kundenname enthält verbotene Zeichen.\n");
+        return ERRORRETURN;
+    }
+    for (int i = 0; i < ARRSIZE; i++) {
+        if (customers[i].id == -1) {
+            customers[i] = *new_customer;
+            return 0;
+        }
+    }
+    printf("Es können keine weiteren Kunden hinzugefügt werden.\n");
+    return ERRORRETURN;
+}
+
+int print_customer() {
+    printf("**********************\n");
+    printf("* WWS Kundenausgabe *\n");
+    printf("**********************\n");
+    printf("Bitte geben Sie ihre Kundennummer ein: ");
+    int id = get_clean_int();
+    if (id == ERRORRETURN) {return ERRORRETURN;}
+    int wanted_index = find_customer(id);
+    if (wanted_index == ERRORRETURN) {
+        printf("Die eingegebene Kundennummer konnte nicht gefunden werden.");
+        return ERRORRETURN;
+    }
+    Customer customer = customers[wanted_index];
+    printf("Kundennumer: %d\n", customer.id);
+    printf("Name: %s\n", customer.name);
+    return 0;
+}
+
+int menu() {
+    printf("**********************\n");
+    printf("*   WWS Menüsystem   *\n");
+    printf("**********************\n");
+    printf("1: Produkteingabe\n");
+    printf("2: Produktausgabe\n");
+    printf("3: Kundeneingabe\n");
+    printf("4: Kundenausgabe\n");
+    printf("5: Verlassen\n");
+    printf("Auswahl: ");
+    int input = get_clean_int();
+    switch (input) {
+        case 1:
+            add_product();
+            break;
+        case 2:
+            print_product();
+            break;
+        case 3:
+            add_customer();
+            break;
+        case 4:
+            print_customer();
+            break;
+        case 5:
+            printf("Das System wird verlassen...\n");
+            return EXITVAL;
+    }
+    return 0;
+}