有关 cout.setfill 的错误

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   Standard C++ Library
               Copyright 1998, Rogue Wave Software, Inc.

NAME
   cout

   - Controls output to a stream buffer associated with the object
   stdout declared in <cstdio>.

SYNOPSIS
   #include <iostream>
   extern ostream cout;
   ostream cout;

DESCRIPTION
   The object cout controls output to a stream buffer associated with the
   object stdout declared in <cstdio>. By default the standard C and C++
   streams are synchronized, but performance improvement can be achieved
   by using the ios_base member function synch_with_stdio to
   desynchronize them.

   After the object cin is initialized, cin.tie() returns &cout, which
   implies that cin and cout are synchronized.

FORMATTING
   The formatting is done through member functions or manipulators.

   MANIPULATORS  MEMBER FUNCTIONS

   showpos    setf(ios_base::showpos)

   noshowpos    unsetf(ios_base::showpos)

   showbase    setf(ios_base::showbase)

                                 - 1 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   noshowbase    unsetf(ios_base::showbase)

   uppercase    setf(ios_base::uppercase)

   nouppercase    unsetf(ios_base::uppercase)

   showpoint    setf(ios_base::showpoint)

   noshowpoint    unsetf(ios_base::showpoint)

   boolalpha    setf(ios_base::boolalpha)

   noboolalpha    unsetf(ios_base::boolalpha)

   unitbuf    setf(ios_base::unitbuf)

   nounitbuf    unsetf(ios_base::unitbuf)

   internal    setf(ios_base::internal,
                     ios_base::adjustfield)

   left    setf(ios_base::left,
               ios_base::adjustfield)

   right    setf(ios_base::right,
                  ios_base::adjustfield)

                                 - 2 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   dec    setf(ios_base::dec,
               ios_base::basefield)

   hex    setf(ios_base::hex,
               ios_base::basefield)

   oct    setf(ios_base::oct,
               ios_base::basefield)

   fixed    setf(ios_base::fixed,
                  ios_base::floatfield)

   scientific    setf(ios_base::scientific,
                     ios_base::floatfield)

   resetiosflags
      (ios_base::fmtflags flag)    setf(0,flag)

   setiosflags
      (ios_base::fmtflags flag)    setf(flag)

   setbase(int base)    see above

   setfill(char_type c)    fill(c)

   setprecision(int n)    precision(n)

   setw(int n)    width(n)

                                 - 3 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   endl

   ends

   flush    flush( )

DESCRIPTION
   showpos Generates a + sign in non-negative generated numeric output.

   showbase Generates a prefix indicating the numeric base of generated
               integer output

   uppercase Replaces certain lowercase letters with their uppercase
               equivalents in generated output

   showpoint Generates a decimal-point character unconditionally in
               generated floating-point output

   boolalpha Inserts and extracts bool type in alphabetic format

   unitbuf Flushes output after each output operation

   internal Adds fill characters at a designated internal point in
               certain generated output. If no such point is designated,
               it's identical to right.

   left Adds fill characters on the right (final positions) of certain
         generated output

   right Adds fill characters on the left (initial positions) of
            certain generated output

                                 - 4 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   dec Converts integer input or generates integer output in decimal
         base

   hex Converts integer input or generates integer output in
         hexadecimal base

   oct Converts integer input or generates integer output in octal base

   fixed Generates floating-point output in fixed-point notation

   scientific Generates floating-point output in scientific notation

   resetiosflags

   (ios_base::fmtflags flag)    Resets the fmtflags field flag

   setiosflags

   (ios_base::fmtflags flag)    Sets up the flag flag

   setbase(int base) Converts integer input or generates integer output
                        in base base. The parameter base can be 8, 10 or
                        16.

   setfill(char_type c) Sets the character used to pad (fill) an output
                           conversion to the specified field width

   setprecision(int n) Sets the precision (number of digits after the
                        decimal point) to generate on certain output
                        conversions

                                 - 5 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   setw(int n) Sets the field with (number of characters) to generate
                  on certain output conversions

   showpos Generates a + sign in non-negative generated numeric output.

   showbase Generates a prefix indicating the numeric base of generated
               integer output

   uppercase Replaces certain lowercase letters with their uppercase
               equivalents in generated output

   showpoint Generates a decimal-point character unconditionally in
               generated floating-point output

   boolalpha Inserts and extracts bool type in alphabetic format

   unitbuf Flushes output after each output operation

   internal Adds fill characters at a designated internal point in
               certain generated output. If no such point is designated,
               it's identical to right.

   left Adds fill characters on the right (final positions) of certain
         generated output

   right Adds fill characters on the left (initial positions) of
            certain generated output

                                 - 6 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   dec Converts integer input or generates integer output in decimal
         base

   hex Converts integer input or generates integer output in
         hexadecimal base

   oct Converts integer input or generates integer output in octal base

   fixed Generates floating-point output in fixed-point notation

   scientific Generates floating-point output in scientific notation

   resetiosflags

   (ios_base::fmtflags flag)    Resets the fmtflags field flag

   setiosflags

   (ios_base::fmtflags flag)    Sets up the flag flag

   setbase(int base) Converts integer input or generates integer output
                        in base base. The parameter base can be 8, 10 or
                        16.

   setfill(char_type c) Sets the character used to pad (fill) an output
                           conversion to the specified field width

   setprecision(int n) Sets the precision (number of digits after the
                        decimal point) to generate on certain output
                        conversions

                                 - 7 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   setw(int n) Sets the field with (number of characters) to generate
                  on certain output conversions

   endl Inserts a newline character into the output sequence and flush
         the output buffer.

   ends Inserts a null character into the output sequence.

   flush Flush the output buffer.

DEFAULT VALUES
   precision()          6
   width()             0
   fill()                the space character
   flags()             skipws | dec
   getloc()             locale::locale()

EXAMPLE
   //
   // cout example #1
   //
   #include<iostream>
   #include<iomanip>

   void main ( )
   {
   using namespace std;

   int i;
   float f;

      // read an integer and a float from stdin
   cin >> i >> f;
      // output the integer and goes at the line
   cout << i << endl;

      // output the float and goes at the line

                                 - 8 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   cout << f << endl;

      // output i in hexa
   cout << hex << i << endl;

      // output i in octal and then in decimal
   cout << oct << i << dec << i << endl;

      // output i preceded by its sign
   cout << showpos << i << endl;

      // output i in hexa
   cout << setbase(16) << i << endl;

      // output i in dec and pad to the left with character
      // @ until a width of 20
      // if you input 45 it outputs 45@@@@@@@@@@@@@@@@@@
   cout << setfill('@') << setw(20) << left << dec << i;
   cout << endl;

      // output the same result as the code just above
      // but uses member functions rather than manipulators
   cout.fill('@');
   cout.width(20);
   cout.setf(ios_base::left, ios_base::adjustfield);
   cout.setf(ios_base::dec, ios_base::basefield);
   cout << i << endl;

      // outputs f in scientific notation with
      // a precision of 10 digits
   cout << scientific << setprecision(10) << f << endl;

      // change the precision to 6 digits
      // equivalents to cout << setprecision(6);
   cout.precision(6);

      // output f and goes back to fixed notation
   cout << f << fixed << endl;

   }
   //
   // cout example #2
   //
   #include <iostream>

   void main ( )
   {
   using namespace std;

                                 - 9 -       Formatted:  June 20, 2006

cout(3C++)                Rogue Wave Software                cout(3C++)
-                                                                      -

                              02 Apr 1998

   char p[50];

   cin.getline(p,50);

   cout << p;
   }
   //
   // cout example #3
   //
   #include <iostream>
   #include <fstream>

   void main ( )
   {
   using namespace std;

      // open the file "file_name.txt"
      // for reading
   ifstream in("file_name.txt");

      // output the all file to stdout
   if ( in )
      cout << in.rdbuf();
   else
      {
         cout << "Error while opening the file";
         cout << endl;
      }
   }

WARNINGS
   Keep in mind that the manipulator endl flushes the stream buffer.
   Therefore it is recommended to use `/n' if your only intent is to go
   at the line. It greatly improves performance when C and C++ streams
   are not synchronized.

   If your compiler does not support namespaces, then you do not need the
   using declaration for std.

SEE ALSO
   basic_ostream(3C++), basic_iostream(3C++), basic_filebuf(3C++),
   cin(3C++), cerr(3C++), clog(3C++), wcin(3C++), wcout(3C++),
   wcerr(3C++), wclog(3C++), iomanip(3C++)

//===========================================================================

void print(Date s){

cout.setfill('0');

cout<<setw(4)<<s.year<<'-'<<setw(2)<<s.month<<'-'<<setw(2)<<s.day<<'/n';

cout.setfill('');

}

//==============================================================================

上面的代码会报错。
应该将cout.setfill改为cout<<setfill

注意：cout<<setfill('c') 引号间必须有字符