milon

joined 1 year ago
[–] milon@lemm.ee 3 points 16 hours ago

Thank you for the thorough explanation. It makes sense to me why I had the error that I did. I'll keep this in mind next time when I consider using a bitwise operator.

[–] milon@lemm.ee 5 points 1 day ago (5 children)

Thank you for the reply. It seems bitwise operators are somewhat of an advanced concept that I may revisit down the road.

[–] milon@lemm.ee 3 points 1 day ago (10 children)

Thanks. I think I understand why I wouldn't want to use it in this case. But what is an example of where I can use it? This makes me think I should avoid using bitwise operators with integers and keep it to strings only, but I know that's not true from what I've learned.

[–] milon@lemm.ee 2 points 1 day ago

Thank you. Not sure why in the link the arithmetic in green results in 7.

[–] milon@lemm.ee 2 points 1 day ago* (last edited 1 day ago)

Thank you for breaking it down.

I'm just now sure when it is appropriate to use '|'. If bitwise operators can only be used with integers (and not floats), what's an example where I can use it.

[–] milon@lemm.ee 1 points 1 day ago

Yes I did eventually think of that as well but just wanted to understand why '|' wasn't producing the results I expected.

[–] milon@lemm.ee 1 points 1 day ago (2 children)

I did come across that link but didn't quite understand it. If looking only at 25 | 10, does the code not run as expected because 25 is 5 digits long and 10 is 4 digits long? Is that what's meant by "two equivalent length bit designs"?

Also, I can't tell if 10 | 4 = 7 or 10 | 4 = 14.

 

if coin == 25 | 10 | 5:

If I replace the '|' with 'or' the code runs just fine. I'm not sure why I can't use '|' in the same statement.

Doing the following doesn't work either:

if coin == 25 | coin == 10 | coin == 5:

I know bitwise operators can only be used with integers, but other then that is there another difference from logical operators?

 
 # Ask user to enter an expression and display output
def main():
    expression = input("Expression: ")

    print(calculate(splitter(expression)))


# Split expression into components and assign to variables as float values
def splitter(expression):
    x, y, z = expression.split()

    return x, y, z

# Calculate expression result
def calculate(x, y, z):
    x, z = float(x), float(z)

    if y == "+":
        return str(round((x + z), 1))
    elif y == "-":
        return str(round((x - z), 1))
    elif y == "*":
        return str(round((x * z), 1))
    else:
        return str(round((x / z), 1))



main()

I am getting traceback errors for any expression (1 + 1) I enter.

[–] milon@lemm.ee 1 points 1 year ago (1 children)

Yes - I finally caught that part about n as it's just moving in reverse so it gets decremented. Now I'm not sure about i. In the debugger when the program gets to the for loop both n and i are equal to 1. The n I understand but i?

[–] milon@lemm.ee 1 points 1 year ago

Gotcha. Thanks for the explanation.

[–] milon@lemm.ee 1 points 1 year ago (1 children)

I see. I guess my understanding was that the recursion was over after the recursive call, but it's actually for all the code in draw().

[–] milon@lemm.ee 1 points 1 year ago (1 children)

Thanks. I did see that. I have a general understanding of how recursion works I think where the function calls itself again and again but I don't get why the code (for loop) below the draw(n - 1) is recursive.

[–] milon@lemm.ee 1 points 1 year ago (3 children)

Right. I was aware it was recursion as stated in the title of my post. I had two questions specific to where the for loop returns after printing #.

 

I used the debugger to examine this code but not understanding a couple areas.

  1. Why does the for loop repeat after it exits to print a new line? If it exits the loop, shouldn't it be done with it?
  2. Why is n incremented and not i as stated with i++?

int main(void)
{
    int height = get_int("Height: ");

    draw(height);
}

void draw(int n)
{
    if (n <= 0)
    {
        return;
    }

    draw(n - 1);

    for (int i = 0; i < n; i++)
    {
        printf("#");
    }
    printf("\n");
}
 

This is in C language. When I call rotate() in main, the function returns false for isalpha() even though the string entered for plaintext uses alphabetic characters. Perhaps it's identifying an alphabetic character by its ASCII value ('A' = 65)? I tried to test that out and used (char) with the letter variable in rotate() but it didn't change anything.

PORTION OF MAIN

string plaintext = get_string("plaintext:  ");

    int length = strlen(plaintext);
    char ciphertext[length];

    for (int i = 0; i < length; i++)
    {
        ciphertext[i] = rotate(plaintext[i], key);
    }

ROTATE FUNCTION

char rotate(char letter, int key)
{
    if (isalpha(letter) == true)
    { ...
 

In VS I am told this function "does not return a value in all control paths." A bot told me specifically the issue is with this line: else if (letter + key <= 90). It said that if the outcome results in letter + key equally exactly 90 then a value is not returned, but I thought that was covered where '<=' means 'less than or equals.'

char rotate(char letter, int key)
{
    if (isalpha(letter) == true)
    {
        if (letter + key > 90)
        {
            int overage = letter + key - 90;
            letter = 64 + overage;

            while (letter > 90)
            {
                overage = letter - 90;
                letter += overage;
            }

            return letter;
        }

        else if (letter + key &lt;= 90)
        {
            letter += key;
            return letter;
        }
    }

    else if (isalpha(letter) == false)
    {
        return letter;
    }
13
submitted 1 year ago* (last edited 1 year ago) by milon@lemm.ee to c/programming@programming.dev
 

What is %.2f? Why is it not just %f? Is there some additional calculation happening? The half function already does all the calculations including splitting the bill, so I'm not sure what %.2f is. (Btw why is this code not formatting correctly in lemmy?)


#include 
#include 

float half(float bill, float tax, int tip);

int main(void)
{
    float bill_amount = get_float("Bill before tax and tip: ");
    float tax_percent = get_float("Sale Tax Percent: ");
    int tip_percent = get_int("Tip percent: ");

    printf("You will owe $%.2f each!\n", half(bill_amount, tax_percent, tip_percent));
}

// TODO: Complete the function
float half(float bill, float tax, int tip)
{
    bill += (bill * (tax / 100.0));
    bill += (bill * (tip / 100.0));

    bill /= 2;

    return bill;
}
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