kaleidoscope problem my program is rounding the second decimal place one less than what its supposed to be

Question

Can anyone tell me what I wrote wrong

#include <stdio.h>
int main()
{
float price,n;
scanf("%f",&n);
if(n==1)
{
price=5;
}
else if(n>1)
{
price=(5*n)-((5*n)*0.1);
}
price+=price*0.07;
printf("%.2f",price);
return 0;
}

Answer 1

https://code.sololearn.com/cT2wj02h5IpO/?ref=app

fixed it

Answer 2

well, first of all it's weird that you're making n a float instead of an int, and it's maybe possible there are some rounding consequences from that . . . but that aside if you think it's a rounding problem, you can:
a) switch to doubles
b) try to cut down on the number of separate operations (ie bake taxes into the n=1 case and combine *0.9 and *1.07 into a single operation, instead of doing the taxes separately)

There's another possibility though, which is that they secretly want you to always round up fractions of a cent (which would be pretty common in real-world business practice, but they still really should have stated it explicitly if so), in which case you'd probably just wanna include Math.h and use ceil(). I don't know if that's what they wanted here, but I would try this approach first anyway, since rounding errors are much messier to troubleshoot

Answer 3

Hello!
Please, upload a private code with your snippet.
You should read this: https://code.sololearn.com/Wek0V1MyIR2r/?ref=app

Answer 4

https://www.sololearn.com/Discuss/3085069/?ref=app
https://www.sololearn.com/Discuss/2486871/?ref=app

Answer 5

You can try using ceil() (remember to #include <math.h>)

Answer 6

That's not really a solution more like a way around the problem 🤔

Answer 7

I first declared n as int itself but that still didn't solve it so I tried making n a float to see if itll fix anything but it didn't

Answer 8

https://code.sololearn.com/cT2wj02h5IpO/?ref=app

Answer 9

I tried it still isn't working 🥲giving thr same output

Answer 10

But when I add 0.001 to the price it passes all the test cases
so it's definitely a small round up error

Answer 11

And what if you try adding 0.001 to the result?

Answer 12

0.01 doesn't work but 0.001 works

Answer 13

So it is solved no?

Answer 14

Well if ceil didn't fix it, then try using doubles, and if that's not enough somehow, replace
price = 5 with price = 5*1.07 (or just 5.35), and
price = (5*n)...etc with price = n*5*0.9*1.07 (or just n*4.815), and delete price += price*0.07

If you still have issues after that, it's probably not a rounding error after all