****[**Cheat Engine**](https://www.cheatengine.org/downloads.php) is a useful program to find where important values are saved inside the memory of a running game and change them.\
When you download and run it, you are **presented** with a **tutorial** of how to use the tool. If you want to learn how to use the tool it's highly recommended to complete it.
**Usually numbers** are stored in **4bytes** form, but you could also find them in **double** or **float** formats, or you may want to look for something **different from a number**. For that reason you need to be sure you **select** what you want to **search for**:
In _**Edit --> Settings --> Hotkeys**_ you can set different **hotkeys** for different purposes like **stopping** the **game** (which is quiet useful if at some point you want to scan the memory). Other options are available:
Once you **found** where is the **value** you are **looking for** (more about this in the following steps) you can **modify it** double clicking it, then double clicking its value:
The **change** to the **memory** will be immediately **applied** (note that until the game doesn't use this value again the value **won't be updated in the game**).
So, we are going to suppose that there is an important value (like the life of your user) that you want to improve, and you are looking for this value in the memory)
Cheat Engine will search for the **values** that **went from 100 to the new value**. Congrats, you **found** the **address** of the value you were looking for, you can now modify it.\
Until know we learnt how to find an address storing a value, but it's highly probably that in **different executions of the game that address is in different places of the memory**. So lets find out how to always find that address. 
Using some of the mentioned tricks, find the address where your current game is storing the important value. Then (stopping the game if you whish) do a **right click** on the found **address** and select "**Find out what accesses this address**" or "**Find out what writes to this address**":
The **first option** is useful to know which **parts** of the **code** are **using** this **address** (which is useful for more things like **knowing where you can modify the code** of the game).\
The **second option** is more **specific**, and will be more helpful in this case as we are interested in knowing **from where this value is being written**.
Once you have selected one of those options, the **debugger** will be **attached** to the program and a new **empty window** will appear. Now, **play** the **game** and **modify** that **value** (without restarting the game). The **window** should be **filled** with the **addresses** that are **modifying** the **value**:
Now that you found the address it's modifying the value you can **modify the code at your pleasure** (Cheat Engine allows you to modify it for NOPs real quick):
Following the previous steps, find where the value you are interested is. Then, using "**Find out what writes to this address**" find out which address writes this value and double click on it to get the disassembly view:
Now, click on the "Pointer" check box and add the found address in the text box (in this scenario, the found address in the previous image was "Tutorial-i386.exe"+2426B0):
Code injection is a technique where you inject a piece of code into the target process, and then reroute the execution of code to go through your own written code (like giving you points instead of resting them).
So, insert your new assembly code in the "**newmem**" section and remove the original code from the "**originalcode**" if you don't want it to be executed**.** In this example the injected code will add 2 points instead of substracting 1:
