Customize your environment to have your tools for software development ready to use.
For now, only what we want to have to create programs which are then run within the virtual terminal.
There will be a next part later.
By following along with me, you know what there is to say about what we are going to use here.
Just, as usual, further adjusting to your personal taste, which may include your preference of programming languages.
*(* → Hint; *)*

Wanted is the sum of numbers 1 .. n.
First, think of a formula to use for it.
Then provide a proof for it.
*(* → Hint; *)*

We have as given:
The larger to the smaller is equal to the ratio of the sum of both to the larger.
Wanted is this number which corresponds to this ratio.
*(* → Hint; *)*

Find out about the formula for the sequence of numbers by which the idea growth is expressed in the most natural manner.
Beginning with a simple, recursive definition, first implement it like this, and then rewrite it in a more efficient way and compare the results.
*(* → Hint; *)*

Write a program to draw a random trail towards the border of the board used as playground.
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Implement as a linked list what can be used in queue‑like fashion.
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Implement a list of arrays of permutations of the initial array of items 1 .. n.
How many of them will that be?
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Write something which will be useful to get card decks shuffled.

Implement what can be used as a selfâ€‘balancing tree.
*(* → Hint; *)*

Calculate prime numbers.
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Find out how to extend other languages using C to switch terminal to immediate mode; changing back to normal mode afterwards. Thereby width and height of the screen is made available. And a proc should be provided by which some useful code is returned by which one can retrieve the information about what plain character was typed in or what kind of special key was pressed.

Implement what can be used to create your first simple game using the terminal capabilites; and then actually do it!
*(* → Hint; *)*

Implement something to provide flexible arrays for C. It should be usable to insert items such that the array is maintained sorted. Implement a proc for binary search for that, which can also be used as such.