floating point values not displaying accurate number of digits c++

Question

Having trouble giving the correct digits for my $ output.

every time i plug in for example 8 in the statement i get numbers with 3 digits Ex. 10.9 While i would like it to display $10.90

I just added the setprecision hoping that it will fix the issue, did not work

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


int main()
{
    int Ts;    // holds Ts 
    float Price, Tcost, Total;


    cout << "How many shirts you like ?" << endl;
    cin >> Ts;

    Total = 12 * Ts;

    if ( 5 < Ts && Ts < 10)
        Tcost = (Total - (.10 * Total));
        Price = (Tcost / Ts);
        cout << "he cost per shirt is $" << setprecision(4) << Price << " and the total cost is $" << Tcost << setprecision(4) << endl;




    return 0;


}

Can you please edit your question to show the *expected* output as well as the *actual* output. In full. — Some programmer dude, Feb 15 '18 at 02:26
Oh and remember that C++ isn't Python. Indentation is nice to have since it makes it easier to read, but it's not relevant to scoping. You're missing a couple of curly-braces `{}`. This is something that every [good beginners book](https://stackoverflow.com/a/388282/440558) (and even bad ones) would have told you. — Some programmer dude, Feb 15 '18 at 02:27
StackOverflow would be a more welcoming and useful resource if people spent more time helping the newbies and less time criticizing them over minor details. — Jeremy Friesner, Feb 15 '18 at 02:30
I don't get it. Total = 96, Then Tcost = Total - 9.6, which is 86.4. Price = 86.4/8, which is 10.8. This is somewhat close to your answer (Floating point disrepancies). What are you expecting? — Arnav Borborah, Feb 15 '18 at 02:32
The code that i get from my professor doesn't have the {} curly-braces if that is what you are talking about @Someprogrammerdude — BlackHawkD721, Feb 15 '18 at 02:33
I recommend testing against input of 12 to see the bug Some programmer dude brought up about the missing braces. — user4581301, Feb 15 '18 at 02:51
If you want more than one statement inside an `if` you need the curly-braces. I suspect the professor expects you to think a little for yourself. — Some programmer dude, Feb 15 '18 at 03:01

Arnav Borborah · Answer 1 · 2018-02-15T02:41:40.137

2

Use a combination of std::fixed(Which will set the amount of decimals after the point to be printed as decided by setprecision(N)) and std::setprecision(2) (So that two decimals are printed), and the code should now work:

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


int main()
{
    int Ts;    // holds Ts 
    float Price, Tcost, Total;


    cout << "How many shirts you like ?" << endl;
    cin >> Ts;

    Total = 12 * Ts;

    if ( 5 < Ts && Ts < 10)
        Tcost = (Total - (.10 * Total));
        Price = (Tcost / Ts); // The indentation is weird here
                              // but I will leave it as it is
        cout << "he cost per shirt is $" << fixed << setprecision(2) << Price << " and the total cost is $" << Tcost << setprecision(2) << endl;
    return 0;


}

The output I get from this is:

How many shirts you like ?
8
he cost per shirt is $10.80 and the total cost is $86.40

edited Feb 15 '18 at 02:41

answered Feb 15 '18 at 02:39

Arnav Borborah

11,357
8
43
88

Thanks, i tried using the fixed and it didnt work before . – BlackHawkD721 Feb 15 '18 at 02:41
yes it does i took the same format of this and tried to run it in different values and im getting problems where its displaying the cout 4 times with no values – BlackHawkD721 Feb 15 '18 at 02:55
@BlackHawkD721 Could you give an example of input that isn't working? I tried this will all values from 6-9, and it works for me. – Arnav Borborah Feb 15 '18 at 11:36

score 0 · Answer 2 · answered Feb 15 '18 at 02:35

0

You have to write std::cout.setf(std::ios::showpoint); then it will work.

answered Feb 15 '18 at 02:35

BAE HA RAM

465
1
3
10

Why would i have to put that in when previously i just kept it as 'cout' ?? – BlackHawkD721 Feb 15 '18 at 02:39
because std::cout don't show decimal point zero. So u must set the format of cout for show decimal point zero. – BAE HA RAM Feb 15 '18 at 02:49
The answer is correct, but not complete, unfortunately, @BlackHawkD721 . [The `setf` function](http://en.cppreference.com/w/cpp/io/ios_base/setf) sets a stream formatting option. [`std::ios::showpoint` is the option set](http://en.cppreference.com/w/cpp/io/ios_base/fmtflags), but you may find `cout << "The cost per shirt is $" << showpoint << setprecision(4) << Price << " and the total cost is $" << Tcost << endl;` a little more familiar. You will need to add `#include `. [Docs on `showpoint`](http://en.cppreference.com/w/cpp/io/manip/showpoint) – user4581301 Feb 15 '18 at 02:49

floating point values not displaying accurate number of digits c++

2 Answers2