格式化输入输出

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

int main()
{
    cout<<"default bool values: "<<true<<" "<<false<<"\nalpha bool value: "<<boolalpha<<true<<" "<<false<<endl;
    cout<<noboolalpha<<endl;
    cout<<"default: "<<20<<" "<<1924<<endl;
    cout<<"octal: "<<oct<<20<<" "<<1024<<endl;
    cout<<"hex: "<<hex<<20<<" "<<1024<<endl;
    cout<<"decimal: "<<dec<<20<<" "<<1024<<endl;
    cout<<endl;
    cout<<showbase;
    cout<<uppercase<<"default: "<<20<<" "<<1924<<endl;
    cout<<uppercase<<"octal: "<<oct<<20<<" "<<1024<<endl;
    cout<<uppercase<<"hex: "<<hex<<20<<" "<<1024<<endl;
    cout<<uppercase<<"decimal: "<<dec<<20<<" "<<1024<<endl;
    cout<<nouppercase<<noshowbase;
    cout<<showbase<<"hex: "<<hex<<20<<" "<<1024<<noshowbase<<endl;
    cout<<dec;
    cout<<endl;
    cout<<"precision: "<<cout.precision()<<",Value: "<<sqrt(2.0)<<endl;
    cout.precision(12);
    cout<<"precision: "<<cout.precision()<<",Value: "<<sqrt(2.0)<<endl;
    cout<<setprecision(3);
    cout<<"precision: "<<cout.precision()<<",Value: "<<sqrt(2.0)<<endl;
    cout<<"default format: "<<100*sqrt(2.0)<<‘\n‘
        <<"scientific: "<<scientific<<100*sqrt(2.0)<<‘\n‘
        <<"fixed decimal: "<<fixed<<100*sqrt(2.0)<<‘\n‘;
       // <<"hexadecimal: "<<std::hexfloat<<100*sqrt(2.0)<<‘\n‘
        //<<"use defaults: "<<defaultfloat<<100*sqrt(2.0)<<"\n\n"
    cout<<endl;
    int i=-16;
    double d=3.14159;
    cout<<"i: "<<setw(12)<<i<<"next col"<<‘\n‘
        <<"d: "<<setw(12)<<d<<"next col"<<‘\n‘;
    cout<<left
        <<"i: "<<setw(12)<<i<<"next col"<<‘\n‘
        <<"d: "<<setw(12)<<d<<"next col"<<‘\n‘
        <<right;
    cout<<right
        <<"i: "<<setw(12)<<i<<"next col"<<‘\n‘
        <<"d: "<<setw(12)<<d<<"next col"<<‘\n‘;
    cout<<internal
        <<"i: "<<setw(12)<<i<<"next col"<<‘\n‘
        <<"d: "<<setw(12)<<d<<"next col"<<‘\n‘;
    cout<<setfill(‘#‘)
        <<"i: "<<setw(12)<<i<<"next col"<<‘\n‘
        <<"d: "<<setw(12)<<d<<"next col"<<‘\n‘
        <<setfill(‘ ‘);
    char ch;
    cin>>noskipws;
    while(cin>>ch)
        cout<<ch;
    cin>>skipws;
}