Kaleidoscope code coach c++

Question

I’m close but I can’t seem round to the 2nd
decimal properly

#include <iostream>
#include <iomanip>
using namespace std;

int main() {

int order;
cin >> order;
float total = order * 5;
float totalAfter;
float discount =total - (total * 0.1);

if (order > 1) {
totalAfter = discount + (discount * 0.07);
printf("%.2f", totalAfter);

}
else {
totalAfter = total + (total * 0.07);
printf("%.2f", totalAfter);
}

return 0;
}

I also used fixed << setprecision
But that didn’t work either.

Answer 1

HungryTradie thank you for the advice i very much appreciate it. Do you have any idea why when the input is 3 and i round it outputs 14.44 instead of 14.45?

Answer 2

zack , HungryTradie
I had a play with your code zack incorporating cei() from the Math module.

I have also used cout instead of printf for one of the outputs to show that both options work.

I haven't tested against the challenge, so don't know if this is what you need - let me know

#include <iostream>
#include <iomanip>
#include <math.h>
using namespace std;

int main() {

int order;
cin >> order;
float total = order * 5;
float totalAfter;
float discount = total * 0.9;

if (order > 1) {
totalAfter = discount + (discount * 0.07);
printf("%.2f", ceil(totalAfter*100)/100);
//cout << ceil(totalAfter*100)/100;

}
else {
totalAfter = total + (total * 0.07);
//printf("%.2f", ceil(totalAfter*100)/100);
cout << ceil(totalAfter*100)/100;
}

return 0;
}

Answer 3

Multiplying by a decimal is a lot like dividing. Dividing causes some conversion errors when base10 converts to binary and back to base10. Often they are of minor magnitude, but this one seems to be causing you grief.

There is most probably something like math.round.ceil function that would round up and adjust your output to 2 decimal places, but I don't know it for C++.

Add 0.004 to your total. (Give a tradie a hammer and every problem becomes a nail 🔨🐒)

Answer 4

There is probably a correct way to do this.... But +0.004

Answer 5

zack
The code seems to work correctly, are you trying to round up?

Answer 6

G'day Rik Wittkopp how ya gar'n?

It's Kaleidoscope code challenge

TestCase1: input 1 gives 5.35 output

TestCase2: input 3 gives 14.45 output // Zacks code gave 14.44

Adding 0.005 to the total made test case 4 fail, but adding 0.004 passed all tests. Is there a way to use cout with format specifiers like printf?

Answer 7

HungryTradie thank you

Answer 8

Hey zack nice code mate.
Some other things I reckon you can do to help yourself as a learning programmer:

Try to save lines:
in this program, you could move any code that is the same outside of the decision. Eg the printf() line is completely the same.

Try to use as few variables as you need:
in this program, you use total & totalAfter, but total doesn't get used again, so you could just update total. You use discount before your decision, you could move it inside the decision & you could just update total to have the discount value (before you calculate the tax). You could then move the tax calculation outside the decision instead of needing to write that line twice, put it just above the relocated printf().

Hey, this is C++, why are you using printf() instead of cout <<

Nice work though mate, smash those code coach challenges!

Answer 9

Rik Wittkopp it works for most of the tests, but on one of them the input is 3 and it comes out as 14.445 or when i attempt to round it comes out 14.44 instead of 14.45

Answer 10

Rik Wittkopp no its the kaleidoscope coad coach challenge

Answer 11

zack
Is it challenge 17.2
"Who doesn't love a discount"

Answer 12

/* Using only the basic tools as expected in a Code Coach defined as easy ( for ex. one should not need extra #include statements or methods not yet taught...) : */

#include <iostream>
using namespace std;

int main() {

int unit = 5;
float tax = .07;
float disc = .1;
int sales;
cin >> sales;
float unitDisc = (unit - unit * disc);
float salesDisc = sales * unitDisc + sales * unitDisc * tax;
float mult = (salesDisc + .005) * 100;
int round = mult ;
float out = round ;

if (sales == 1)
{
cout << unit + unit * tax;
}
else cout << out/100 ;

return 0;
}

Full commented explanations in linked file:
https://code.sololearn.com/c11MOzWyGqL0/?ref=app