我无法获得设置精度以在C ++中工作

Question

I can't get the set precision to work in C++. I keep getting 3 decimal places instead of 1. If I out 7 and 32 in, shootp comes out as 21.875. I need it to come out as 21.9. I am fairly new at this and I could use any help! Thanks

#include <iostream>
#include <iomanip>

using  namespace std;

int main()
{
    int scored, attmp;

    cout<<"Enter the number of goals that were scored: ";
    cin>> scored;                                                   

    if( scored < 0 )
    {
        cout<<"Error: The number of goals must be greater than 0. Try Again: 
        ";
        cin>> scored; 
    }

    if( scored > 0 )
    {

    }
    cout<<"\nEnter the number of shots that were attempted: ";
    cin>>attmp;                                                     

    if( attmp < 0 )
    {
        cout<<"Error: The number of goal must be greater that 0. Try again: 
        ";
        cin>> attmp;
    }

    if( attmp >0 )
    {

    }

    double shootp= ((double)scored) / (attmp) * 100.0;      

    cout<<"\nThe Shooting Percentage is "<< shootp << setprecision(1) << 
endl;   
return 0;       
}

Answer 1

You need to use both std::fixed manipulator and std::setprecision object prior to outputting the floating point variable:

std::cout << "The Percentage is " << std::fixed << setprecision(1) << shootp << '\n';

This will result in the output of 21.9 . Using std::setprecision alone will result in 2e+01 on standard output.

Answer 2

在执行输出之前，需要设置精度。

cout << "\nThe Shooting Percentage is " << setprecision(1) << shootp << endl;