Rounding off the number (money) and showing

[nedjiaka]

Hi I'm a begginer of C++ and I have been trying to make my program to round off the number for money. For example $12.65515 then it will become $12.66 and $0.01 will be round off. I don't know how to do that I have been searching everywhere and I couldn't find it. Another thing is i want my program to show if the money have been round up/off like Total $12.66, Rounding -$0.01. Thank for your help.

[BettyBoopTS]

here is a good article on rounding numbers and examples:

http://www.cplusplus.com/forum/articles/3638/

[nedjiaka]

yeah that is a good example thanks for that but i dont think it would work in my case

[BettyBoopTS]

here is a link to setprecision which should help:
http://www.cplusplus.com/reference/iostream/manipulators/setprecision/

[OnymousIllusion]

    cout << fixed << setprecision(2); // this will change every float number in your program 
    
    cout << 12.45343 << endl;

or you can do this

    
    cout << fixed << setprecision(2) << 12.45632 << endl; // or you can do it this way and it will only change the float number on this line

[nedjiaka]

yeap the 1st problem is solved but what about showing the number that round off/up ?? like

Amount $15.11
Rounding -$0.01
Total $15.10

???????

[OnymousIllusion]

This works but I'm not sure if this is what your looking for

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main( )
{
    double moneyAmountOne;
    double roundDown;

    cout << fixed << setprecision(2);

    cin >> moneyAmountOne;

    roundDown = moneyAmountOne - 0.01;

    cout << roundDown << endl;

    return( 0 );
}

[TaikoDragon]

if you wanted to find the difference of the rounded number and original you'd want to use a std::stringstream, that way you can set the precision push the number in and then read it out again into a second float value. then you can take the numeric difference and cout all 3 values...

#include <sstream>
#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main( ){
    double inputAmount, difference, roundedAmount;

    stringstream sstream;
    
    cin >> inputAmount;

    sstream << fixed << setprecision(2);
    sstream << inputAmount << flush;
    sstream >> roundedAmount;
    sstream << roundedAmount - inputAmount << flush;
    sstream >> difference;

    cout << inputAmount << endl << difference << endl << roundedAmount << endl;

    return 0;
}

I'm not 100% sure stringstreams support precision but I'm pretty sure it's a stream universal ability. Also I don't off the top of my head know the call to force the stringstream to clear its contents if any, but you'd want to put that between lines 17 and 18.

[OnymousIllusion]

Never seen the sstream do you have a link I can check out to learn more?

Thanks in advance