#include <string>
    string& append( const string& str );
    string& append( const Char* str );
    string& append( const string& str, size_type index, size_type len );
    string& append( const Char* str, size_type num );
    string& append( size_type num, Char ch );
    string& append( input_iterator start, input_iterator end );

The append function either:

For example, the following code uses append to add 10 copies of the '!' character to a string:

     string str = "Hello World";
     str.append( 10, '!' );
     cout << str << endl;

That code displays:

     Hello World!!!!!!!!!!

In the next example, append() is used to concatenate a substring of one string onto another string:

   string str1 = "Eventually I stopped caring... ";
   string str2 = "but that was the '80s so nobody noticed.";
   str1.append( str2, 25, 15 );
   cout << "str1 is " << str1 << endl;

When run, the above code displays:

   str1 is Eventually I stopped caring... nobody noticed.