C++ IO库探索（#include ＜ciomanip＞)

#include 
#include 
#include 
using namespace std;

int main()
{
    cout << "default bool values: " << true << ' ' << false
         << "nalpha bool values: " << boolalpha << true << ' ' << false << endl;
    cout << true <<' '<<  false << endl;
    cout << noboolalpha << true << ' ' << false << endl;
    cout << "deafult: " << 20 << ' ' << 1024 << endl;
    cout << "octal: " << oct << 20 << ' ' << 1024 << endl;
    cout << "hex: " << hex << 20 <<' ' <<  1024 << endl;
    cout << "80 become decimal before: " <<  80 << endl;
    cout << "decimal: " << dec << 20 <<' ' << 1024 << endl;
    cout << showbase;
    cout << "deafult: " << 20 << ' ' << 1024 << endl;
    cout << "octal: " << oct << 20 << ' ' << 1024 << endl;
    cout << "hex: " << hex << 20 <<' ' <<  1024 << endl;
    cout << "80 become decimal before: " <<  80 << endl;
    cout << "decimal: " << dec << 20 <<' ' << 1024 << endl;
    cout << noshowbase;
    cout << uppercase << showbase << "using upper in hex: " << hex << 20 <<' ' <<  1024
         << nouppercase << noshowbase << dec << endl;
    cout << "Precision: " << cout.precision() <<  " ,value: " << sqrt(3.0) << endl;
    cout.precision(12);
    cout << "Precision: " << cout.precision() <<  " ,value: " << sqrt(3.0) << endl;
    cout << setprecision(3);
    cout << "Precision: " << cout.precision() <<  " ,value: " << sqrt(3.0) << endl;
    cout << "deafult format " << 100*sqrt(3.0) << 'n';
    cout <<"scientific " << scientific << 100*sqrt(3.0) << 'n';
    cout << "fixed decimal: " < 
 
 
代码结果：
 
 
 
default bool values: 1 0
 alpha bool values: true false
 true false
 1 0
 deafult: 20 1024
 octal: 24 2000
 hex: 14 400
 80 become decimal before: 50
 decimal: 20 1024
 deafult: 20 1024
 octal: 024 02000
 hex: 0x14 0x400
 80 become decimal before: 0x50
 decimal: 20 1024
 using upper in hex: 0x14 0x400
 Precision: 6 ,value: 1.73205
 Precision: 12 ,value: 1.73205080757
 Precision: 3 ,value: 1.73
 deafult format 173
 scientific 1.732e+002
 fixed decimal: 173.205
 hex :0xa.d34802c27df28p+4
 using deafult : 173
 10
 10.0 10.0
 i:          -12next col
 db: 3.14next col
 i:          -12next col
 db:         3.14next col
 i: -12         next col
 db: 3.14        next col
 i:          -12next col
 db:         3.14next col
 i: *********-12next col
 db: ********3.14next col
 Hello world!
 Precision: 3 ,value: 1.73205080757
 Precision: 12 ,value: 1.73205080757
 Precision: 12 ,value: 1.732050808
 Precision: 10 ,value: 5
 10 10000000
 00003
     3