编译器提示 ios sflags 未声明,可是我已经写过 #include <iomanip>了 .书上没找到原因.

#include

``` cout<<setiosflags(ios::fixed) << setprecision(2 )
         << C1 <<endl << Sa <<endl << Sb << Va <<endl
         << Vb <<endl ;

试试看下面的程序

#include <iostream>
#include <iomanip>

int main () {
  std::cout << std::hex;
  std::cout << std::setiosflags (std::ios::showbase | std::ios::uppercase);
  std::cout << 100 << std::endl;
  return 0;
}

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

int main()
{
    double a = 12.345;
    double b = 87.888;
    double c = 1.0;
    cout <<setprecision(2) << setiosflags(ios::fixed) << a << "\t" << b << "\t" << c << endl;
    return 0;
}

12.35 87.89 1.00