用流控制成员函数输出数据

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;
int main(int argc, char** argv) {
    int a=21;
    cout.setf(ios::showbase);
    cout<<"dec:"<<a<<endl;
    cout.unsetf(ios::dec);
    cout.setf(ios::hex);
    cout<<"hex:"<<a<<endl;
    cout.unsetf(ios::hex);
    cout.setf(ios::oct);
    cout<<"oct:"<<a<<endl;
    cout.unsetf(ios::oct);
    char *pt="China";
    cout.width(10);
    cout<<pt<<endl;
    cout.width(10);
    cout.fill('*');
    cout<<pt<<endl;
    double pi=22.0/7.0;
    cout.setf(ios::scientific);
    cout<<"pi=";
    cout.width(14);
    cout.width(14);
    cout<<pi<<endl;
    cout.unsetf(ios::scientific);
    cout.setf(ios::fixed);
    cout.width(12);
    cout.setf(ios::showpos);
    cout.setf(ios::internal);
    cout.precision(6);
    cout<<pi<<endl;
    return 0;
}