spark current
Hi! I was doing some practice questions on recursion and i was having some trouble with this problem. I cant seem to figure out the logic behind it. I'm required to use up to four helper recursive functions and no loops
I have to make this pattern on the terminal:
mossy iglooBOT
silk musk
Hi! I was doing some practice questions on recursion and i was having some troub...
What code do you have so far?
spark current
That's the problem, i can't figure out what logic to apply
Having trouble with logic
silk musk
That's the problem, i can't figure out what logic to apply
It'd help us to know what problems you've already solved with recursion, so that we don't overexplain nor underexplain
And whether you've got experience with these problems where you have to print a pattern
spark current
i've made basic patterns like triangles and stuff using recursion
like this for example
my main issue is with patterns, i've got a good grasp of recursion otherwise
silk musk
Honestly, if the exercise didn't specify that it was about recursion I would have personally solved it with simple loops alone
spark current
yeah with loops it's easy, but that's the restriction
silk musk
But the challenge I guess is to break it down into simple chunks of code by looking for patterns, like probably needing if (x == 0 && y == 1 && in_window) { // print "R" }
spark current
that's what i'm having trouble figuring out
silk musk
So the thing to realize here is that when you say it's easy with loops, you are essentially saying it's easy with recursion:
void foo(void) {
int i = 0;
while (i < 3) {
printf("%d\n", i);
i++;
}
}
void foo(int i) {
if (i < 3) {
printf("%d\n", i);
foo(i + 1);
}
}
So what I recommend is first writing the exercise with regular loops, and then rewriting that code so it uses recursion in a hamfisted way like this
Of course you'd ideally write the recursive version straight away, but I think this makes it significantly more gentle
silk musk
Let me know if you get stuck making it recursive
silk musk
No worries, and as a further tip, you'll want to have your loop version only use up to a single loop per function, since that makes it way easier to turn it recursive
As seen in the block of code I sent
spark current
sure
spark current
No worries, and as a further tip, you'll want to have your loop version only use...
can you give me some few tips on how you'd do it
that would help
mossy iglooBOT
@spark current Has your question been resolved? If so, type !solved :)
silk musk
can you give me some few tips on how you'd do it
By "it" you mean solving the problem with loops?
silk musk
Well, the first thing that comes to mind looking at the picture you're expected to recreate is that there are four large squares, one in each of the corners
So I'd write something like:
int main(void) {
print_square(-1, -1); // Top-left
print_square(1, -1); // Top-right
print_square(-1, 1); // Bottom-left
print_square(1, 1); // Bottom-right
}
Or actually, I'd pass booleans here
print_square(bool left, bool top);
In order to make your life easier I also recommend making a global 2D char array, so that you can just insert characters into their final position without having to worry about the order things need to be printed
You can also do it without making that array global by passing it into every function, but that'd make the code significantly less readable imo
And if you only need to recreate that specific picture, I recommend hardcoding the width and height directly into the definition of the size like so:
constexpr size_t width = ?;
constexpr size_t height = ?;
char map[height][width];
Good job! Did you end up doing it roughly the way I recommended, where you started out doing it without recursion where every single function contained just a single loop, and you then turned that into recursive functions later?
spark current
Good job! Did you end up doing it roughly the way I recommended, where you start...
i did it in two loops, one handled the rows and one handled the columns, the columns one iterated first, reached the max value and then called a new line, increased the row and set column value back to zero
silk musk
i did it in two loops, one handled the rows and one handled the columns, the col...
So did you use recursion?
I'm required to use up to four helper recursive functions and no loops
silk musk
good job
spark current
thanku
silk musk
i did it in two loops, one handled the rows and one handled the columns, the col...
I presume you used tons of checks like if (x == 42 && y == 69) { printf("R"); } for every row?
