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setw

Specifies the width of the display field.

T6 setw( 
   streamsize _Wide 
);

Parameters

  • _Wide
    The width of the display field.

Return Value

The manipulator returns an object that, when extracted from or inserted into the stream str, calls str.width(_Wide), then returns str.

Example

// iomanip_setw.cpp 
// compile with: /EHsc
// Defines the entry point for the console application.
//
// Sample use of the following manipulators:
//   resetiosflags
//   setiosflags
//   setbase
//   setfill
//   setprecision
//   setw

#include <iostream>
#include <iomanip>

using namespace std;

const double   d1 = 1.23456789;
const double   d2 = 12.3456789;
const double   d3 = 123.456789;
const double   d4 = 1234.56789;
const double   d5 = 12345.6789;
const long      l1 = 16;
const long      l2 = 256;
const long      l3 = 1024;
const long      l4 = 4096;
const long      l5 = 65536;
int         base = 10;

void DisplayDefault( )
{
   cout << endl << "default display" << endl;
   cout << "d1 = " << d1 << endl;
   cout << "d2 = " << d2 << endl;
   cout << "d3 = " << d3 << endl;
   cout << "d4 = " << d4 << endl;
   cout << "d5 = " << d5 << endl;
}

void DisplayWidth( int n )
{
   cout << endl << "fixed width display set to " << n << ".\n";
   cout << "d1 = " << setw(n) << d1 << endl;
   cout << "d2 = " << setw(n) << d2 << endl;
   cout << "d3 = " << setw(n) << d3 << endl;
   cout << "d4 = " << setw(n) << d4 << endl;
   cout << "d5 = " << setw(n) << d5 << endl;
}

void DisplayLongs( )
{
   cout << setbase(10);
   cout << endl << "setbase(" << base << ")" << endl;
   cout << setbase(base);
   cout << "l1 = " << l1 << endl;
   cout << "l2 = " << l2 << endl;
   cout << "l3 = " << l3 << endl;
   cout << "l4 = " << l4 << endl;
   cout << "l5 = " << l5 << endl;
}

int main( int argc, char* argv[] )
{
   DisplayDefault( );

   cout << endl << "setprecision(" << 3 << ")" << setprecision(3);
   DisplayDefault( );

   cout << endl << "setprecision(" << 12 << ")" << setprecision(12);
   DisplayDefault( );

   cout << setiosflags(ios_base::scientific);
   cout << endl << "setiosflags(" << ios_base::scientific << ")";
   DisplayDefault( );

   cout << resetiosflags(ios_base::scientific);
   cout << endl << "resetiosflags(" << ios_base::scientific << ")";
   DisplayDefault( );

   cout << endl << "setfill('" << 'S' << "')" << setfill('S');
   DisplayWidth(15);
   DisplayDefault( );

   cout << endl << "setfill('" << ' ' << "')" << setfill(' ');
   DisplayWidth(15);
   DisplayDefault( );

   cout << endl << "setprecision(" << 8 << ")" << setprecision(8);
   DisplayWidth(10);
   DisplayDefault( );

   base = 16;
   DisplayLongs( );

   base = 8;
   DisplayLongs( );

   base = 10;
   DisplayLongs( );

   return   0;
}

default display d1 = 1.23457 d2 = 12.3457 d3 = 123.457 d4 = 1234.57 d5 = 12345.7 setprecision(3) default display d1 = 1.23 d2 = 12.3 d3 = 123 d4 = 1.23e+003 d5 = 1.23e+004 setprecision(12) default display d1 = 1.23456789 d2 = 12.3456789 d3 = 123.456789 d4 = 1234.56789 d5 = 12345.6789 setiosflags(4096) default display d1 = 1.234567890000e+000 d2 = 1.234567890000e+001 d3 = 1.234567890000e+002 d4 = 1.234567890000e+003 d5 = 1.234567890000e+004 resetiosflags(4096) default display d1 = 1.23456789 d2 = 12.3456789 d3 = 123.456789 d4 = 1234.56789 d5 = 12345.6789 setfill('S') fixed width display set to 15. d1 = SSSSS1.23456789 d2 = SSSSS12.3456789 d3 = SSSSS123.456789 d4 = SSSSS1234.56789 d5 = SSSSS12345.6789 default display d1 = 1.23456789 d2 = 12.3456789 d3 = 123.456789 d4 = 1234.56789 d5 = 12345.6789 setfill(' ') fixed width display set to 15. d1 = 1.23456789 d2 = 12.3456789 d3 = 123.456789 d4 = 1234.56789 d5 = 12345.6789 default display d1 = 1.23456789 d2 = 12.3456789 d3 = 123.456789 d4 = 1234.56789 d5 = 12345.6789 setprecision(8) fixed width display set to 10. d1 = 1.2345679 d2 = 12.345679 d3 = 123.45679 d4 = 1234.5679 d5 = 12345.679 default display d1 = 1.2345679 d2 = 12.345679 d3 = 123.45679 d4 = 1234.5679 d5 = 12345.679 setbase(16) l1 = 10 l2 = 100 l3 = 400 l4 = 1000 l5 = 10000 setbase(8) l1 = 20 l2 = 400 l3 = 2000 l4 = 10000 l5 = 200000 setbase(10) l1 = 16 l2 = 256 l3 = 1024 l4 = 4096 l5 = 65536

Requirements

Header: <iomanip>

Namespace: std

See Also

Reference

iostream Programming

iostreams Conventions

Other Resources

<iomanip> Members