IT PhD Computer Journal

If you are making a Go network application that works with databases and/or javascript, you need to be careful when using the rune data type.

For example, PostgreSQL does not have a data type that matches rune; There are options for storing rune:

1. store in CHAR(1) – then you will need to convert every time you unload from the database like this: []rune(symbolStr)[0]
2. store in BYTEA; unload via w…. make([]byte, 4)
3. or a slightly less obvious variant – store in the database as INT; which is the most relevant.

Plus… Javascript can’t handle runes either. I have to render the output like this: String.fromCharCode(.Icon);

By the way… It’s funny, not all emoji (unicode characters like ) can be stored in rune. Because some of them exceed the size of rune, because they use an extra Unicode selector:

• “🏘️” houses (U+1F3D8 U+FE0F)
• “⛰️” mountain (U+26F0 U+FE0F)
• “🏔️” mountain with snow (U+1F3D4 U+FE0F)

And it’s not just emoji, but just some basic Unicode characters.

So you have to be careful with rune.

The problem is to find in an array of integers a sequence of consecutive numbers whose sum is equal to n.

Our program will read a list of integers (e.g., 5 2 3 4 6 1 4 10 1), followed by one integer n (e.g., 7). Example output:

5 2 3 4 6 1 4 10 1
7
5 + 2 = 7
3 + 4 = 7
6 + 1 = 7

Continue reading →

Based on the list of dungeon raids, find the top player in the guild 🙂 

Example of input:

Continue reading →

Let’s look at some examples of slice programs in Go.

First one… The user enters two rows of numbers. Our task is to collect them in one slice, removing duplicates. As an exercise, we will not use cards, but ordinary slices.

Code:

Continue reading →

Selection sort is a simple sorting algorithm that repeatedly selects the minimum item from the unsorted part of the list and swaps it with the first unsorted item.

Example code in Go:

Continue reading →

О… how much is in this “Chink”-sound!.. We learned to sort by “bubble” back in school (hello, Mr.Obama!). Why not make a code for this sorting in Go? 😀 Even if it is seldom useful, it’s a good exercise for beginners.

Our program will take a string of integers separated by spaces, convert them to a slice of integers and sort the slice in ascending order… Code:

Continue reading →

The user enters any number, letter, word, or whatever he wants, separated by a space. Let’s say he even enters card values (poker hand), such as A 3 J Q 10. Our job is to shuffle these cards.

To do this, it’s cool (and easy) to use the Fisher-Yates Algorithm. This algorithm works by iterating the array starting with the last element, and replacing the current element with a randomly chosen element. The process is repeated until the first element is reached. The result is a randomly shuffled array.

Here is my fiddly code for this “shuffle.”

Continue reading →

Let’s write a simple console calculator that performs basic arithmetic operations. First, we give it the numbers with which we want to perform operations using the add <number> command (we can give several numbers). Then we can use the commands inc, acc, sub, mul, div, mod; to do calculations: we enter the index of the number to work with and then the operator arguments. Show can be used to display the numbers entered earlier; exit to exit the program.

Example output:
add 42 13
Operands: 42 13
inc 0 1
[43 13]
mod 1 3
[43 1]
exit

Continue reading →

The most cumbersome for newcomers to golang are the interfaces. Here are some examples of code I took apart to “smoke” them, I hope they will help you too. The idea is to look at the code, then close it and from memory try to write from scratch according to this plan:

• write the code through the usual functions
• turn functions into methods
• add an interface

Example number one:

Continue reading →

Assignment number 26 in the Go Tour.

Implement a Fibonacci function that returns a function (closure) that returns consecutive Fibonacci numbers (0, 1, 1, 1, 2, 3, 5, …).

Solution:

Continue reading →

So, there we have exercise 23 from Go Tour.

Implement the WordCount function. It should return a map (data type map) of the counts of each “word” in the string s. The function wc.Test runs a set of tests against the provided function and outputs success or failure. It makes sense to use the strings.Fields function to perform the task.

Solution: Continue reading →

From chapter 18 of Go tour.. In general, the tasks in this ‘tour’ are quite itchy B) So…

Implement the Pic function. It should return a fragment of length dy, each element of which is a fragment of dx 8-bit unsigned integers. When you run the program, it will display your picture by interpreting the integers as grayscale (or blue) values. It will draw something like the picture on the left..
Continue reading →

The last example on Pythagoras’ theorem is quite simple. Let’s take a problem from the same topic, but more complicated. Suppose we have a circle in the center of x-axis and y-axis (i.e. center at coordinates 0,0). Let’s write a test for finding an arbitrary point inside the circle.

Here again Pythagoras will help us. In the general case, the formula is as follows:

Continue reading →