Rust-04: More operators and loops

2022-07-16 Programming Rust Tutorials Niclas Roßberger

In the last post we improved the simple program to be extendable with other operators. In this post we will implement more operators and a loop. Let’s start with the simple task: adding more operators. To support more operators we have to change two parts of the calculator, the parsing and the evaluation. First let’s look into changing the parser. For this we simply add the new operators (-*/) to the regex inside Operation::from_string. Continue reading

Rust-03: Improving the simple program

2022-04-11 Programming Rust Tutorials Niclas Roßberger

In the last post we created a simple program that would accept an input like 5+5 and calculates the result. In this post we will improve this program. To prepare for adding more operators we need to improve the input-parsing. Currently, we just split the input-string at the plus-sign. If we want to know the operator, we have to choose another approach. In this case I chose regex: #[derive(Debug)] struct Operation { left: i32, operator: char, right: i32, } impl Operation { fn from_string(input: &String) -> Option<Operation> { let regex = Regex::new(r"^\s*(\d+)\s*([+])\s*(\d+)\s*$"). Continue reading

Rust-02: The beginning

2022-03-25 Programming Rust Tutorials Niclas Roßberger

At first, I didn’t like Rust. Managing memory myself is something I don’t want to do. After a first look at Rust and setting it aside for a few weeks, it appeared back on my radar. I thought: “This time I’m looking deeper into it”. So I started by reading the Rust Book; and I’m still reading it and find new concepts that are really clever. One of the first things I discovered is that I do not need to manage memory myself. Continue reading

Rust-01: Why am I learning Rust?

2022-03-01 Programming Rust Tutorials Niclas Roßberger

This is a good question, a very good question. Why am I learning Rust? To begin with, I programmed in a lot of languages so far: C++, Python, Swift, Java, Kotlin and TypeScript to name a few. All languages have some features I missed when programming in other languages. Currently, my favorite languages are Kotlin and TypeScript; with Kotlin having the lead. These languages are expressive, and really nice to write. Continue reading

Automatic VirtualBox module signing for UEFI

2018-04-17 Infrastructure Linux Ubuntu Tutorials Niclas Roßberger

These steps are for all those people who hate to sign the Virtualbox modules every time and don’t want to disable UEFI.

Ubuntu: automatic password for second encrypted disk

2016-12-15 Infrastructure Linux Ubuntu Tutorials Niclas Roßberger

I just encountered the problem that I have to type two passwords at startup, for two encrypted disks. My first disk is encrypted through the Ubuntu installer. After some searching I found the perfect solution for that task. In german, it’s called “Schlüsselableitung”, in English derived keys. But perfect solutions often have a big issue why they don’t work, like here. I’m using Ubuntu 16.04 which uses ´systemd´, and that has problems with derived keys. So I found the second most perfect solution for me, using a key-file. Some people argue that this is a security issue, but the derived key is also obtainable with root rights, just like a key-file. And by the way, your private keys of your certificates are also stored on that disks and nearly nobody complains about that.

Qt Signals & Slots: How they work

2016-12-07 Programming Qt Tutorials Niclas Roßberger

The one thing that confuses the most people in the beginning is the Signal & Slot mechanism of Qt. But it’s actually not that difficult to understand. In general Signals & Slots are used to loosely connect classes. Illustrated by the keyword emit, Signals are used to broadcast a message to all connected Slots. If no Slots are connected, the message “is lost in the wild”. So a connection between Signals & Slots is like a TCP/IP connection with a few exceptions, but this metaphor will help you to get the principle. A Signal is an outgoing port and a Slot is an input only port and a Signal can be connected to multiple Slots.

Older posts