CODEWITHSUNDEEP
c++floating-point-precision
SRYZDN
SRYZDN

Reputation: 305

setprecision and floating point

Running the following code I expect to receive such an output:

Desired output:
Car     Hours    Charge
1        1.5      2.00
2        4.0      2.50
3       24.0     10.00

But the results comes out as follows:

Actual output:
Car     Hours    Charge
1        2       2
2        4       2.5 
3    2e+01      10

Any suggestions that can guide me to use the correct floating point comparison and using setprecision correctly is welcome.

int main()
{
    double hour[3];
    double charge[3];

    double sum_hour = 0;
    double sum_charge = 0;

    for (int i = 0; i < 3; i++)
    {
        cout<<"Enter the hours for car No. "<<i<<": ";
        cin>>hour [i];

        if (hour [i] <= 3)
            {charge [i] = 2.00;}
        if (hour [i] > 3 && hour [i] < 24)
            {charge [i] = (2.00 + (ceil(hour [i] -3))*0.5);}
        if (hour [i] == 24)
            {charge [i] = 10.00;}

        sum_hour  = sum_hour + hour [i];
        sum_charge = sum_charge + charge [i];
    }

    cout<<"Car"<<setw(10)<<"Hours"<<setw(10)<<"Charge"<<endl;

    for (int i = 0; i < 3; i++)
    {
        cout<<i+1<<setw(10)<<setprecision(1)<<hour[i]<<setw(10)<<setprecision(2)<<charge[i]<<endl;
    }
    cout<<"TOTAL"<<setw(6)<<sum_hour<<setw(10)<<sum_charge<<endl;

}

Upvotes: 2

Views: 1039

Answers (2)

Hiperon43
Hiperon43

Reputation: 215

You need function fixed to make cout write digits when it got only '0'.

So use it like this:

cout << fixed;
cout<<i+1<<setw(10)<<setprecision(1)<<hour[i]<<setw(10)<<setprecision(2)<<charge[i]<<endl;

Upvotes: 1

Sander De Dycker
Sander De Dycker

Reputation: 16243

std::setprecision by default sets the total number of significant digits that are shown (ie. including the ones before the decimal point).

To set the number of digits shown after the decimal point, use std::fixed :

std::cout << std::fixed << std::setprecision(2) << 24.0;

will display :

24.00

Upvotes: 6

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