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basic_string::assign

Assigns new character values to the contents of a string.

basic_string<CharType, Traits, Allocator>& assign(
    const value_type* _Ptr
);
basic_string<CharType, Traits, Allocator>& assign(
    const value_type* _Ptr,
    size_type _Count
);
basic_string<CharType, Traits, Allocator>& assign(
    const basic_string<CharType, Traits, Allocator>& _Str,
    size_type off, 
    size_type _Count
);
basic_string<CharType, Traits, Allocator>& assign(
    const basic_string<CharType, Traits, Allocator>& _Str
);
basic_string<CharType, Traits, Allocator>& assign(
    size_type _Count, 
    value_type _Ch
);
template<class InIt>
    basic_string<CharType, Traits, Allocator>& assign(
        InputIterator _First, 
        InputIterator _Last
    );
basic_string<CharType, Traits, Allocator>& assign(
    const_pointer _First,
    const_pointer _Last
);
basic_string<CharType, Traits, Allocator>& assign(
    const_iterator _First,
    const_iterator _Last
);

Parameters

  • _Ptr
    A pointer to the characters of the C-string to be assigned to the target string.

  • _Count
    The number of characters to be appended, at most, from the source string.

  • _Str
    The source string whose characters are to be assigned to the target string.

  • _Ch
    The character value to be assigned.

  • _First
    An input iterator, const_pointer, or const_iterator addressing the first character in the range of the source string to be assigned to the target range.

  • _Last
    An input iterator, const_pointer, or const_iterator addressing the one beyond the last character in the range of the source string to be assigned to the target range.

  • off
    The position at which new characters will start to be assigned.

Return Value

A reference to the string object that is being assigned new characters by the member function.

Remarks

The strings can be assigned new character values. The new value can be either a string and C-string or a single character. The operator= may be used if the new value can be described by a single parameter; otherwise the member function assign, which has multiple parameters, can be used to specify which part of the string is to be assigned to a target string.

Example

// basic_string_assign.cpp
// compile with: /EHsc
#include <string>
#include <iostream>

int main( ) 
{
   using namespace std;

   // The first member function assigning the
   // characters of a C-string to a string
   string str1a;
   const char *cstr1a = "Out There";
   cout << "The C-string cstr1a is: " << cstr1a <<  "." << endl;
   str1a.assign ( cstr1a );
   cout << "Assigning the C-string cstr1a to string str1 gives: " 
        << str1a << "." << endl << endl;

   // The second member function assigning a specific
   // number of the of characters a C-string to a string
   string  str1b;
   const char *cstr1b = "Out There";
   cout << "The C-string cstr1b is: " << cstr1b << endl;
   str1b.assign ( cstr1b , 3 );
   cout << "Assigning the 1st part of the C-string cstr1b "
        << "to string str1 gives: " << str1b << "." 
        << endl << endl;

   // The third member function assigning a specific number
   // of the characters from one string to another string 
   string str1c ( "Hello " ), str2c ( "Wide World " );
   cout << "The string str2c is: " << str2c << endl;
   str1c.assign ( str2c , 5 , 5 );
   cout << "The newly assigned string str1 is: " 
        << str1c << "." << endl << endl;

   // The fourth member function assigning the characters
   // from one string to another string in two equivalent
   // ways, comparing the assign and operator =
   string str1d ( "Hello" ), str2d ( "Wide" ), str3d ( "World" );
   cout << "The original string str1 is: " << str1d << "." << endl;
   cout << "The string str2d is: " << str2d << endl;
   str1d.assign ( str2d );
   cout << "The string str1 newly assigned with string str2d is: " 
        << str1d << "." << endl;
   cout << "The string str3d is: " << str3d << "." << endl;
   str1d = str3d;
   cout << "The string str1 reassigned with string str3d is: " 
        << str1d << "." << endl << endl;

   // The fifth member function assigning a specific 
   // number of characters of a certain value to a string
   string str1e ( "Hello " );
   str1e.assign ( 4 , '!' );
   cout << "The string str1 assigned with eclamations is: " 
        << str1e << endl << endl;

   // The sixth member function assigning the value from
   // the range of one string to another string
   string str1f ( "Hello " ), str2f ( "Wide World " );
   cout << "The string str2f is: " << str2f << endl;
   str1f.assign ( str2f.begin ( ) + 5 , str2f.end ( ) - 1 );
   cout << "The string str1 assigned a range of string str2f is: " 
        << str1f << "." << endl << endl;
}
The C-string cstr1a is: Out There.
Assigning the C-string cstr1a to string str1 gives: Out There.

The C-string cstr1b is: Out There
Assigning the 1st part of the C-string cstr1b to string str1 gives: Out.

The string str2c is: Wide World 
The newly assigned string str1 is: World.

The original string str1 is: Hello.
The string str2d is: Wide
The string str1 newly assigned with string str2d is: Wide.
The string str3d is: World.
The string str1 reassigned with string str3d is: World.

The string str1 assigned with eclamations is: !!!!

The string str2f is: Wide World 
The string str1 assigned a range of string str2f is: World.

Requirements

Header: <string>

Namespace: std

See Also

Reference

basic_string Class

Other Resources

basic_string Members