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string::operator+ 

Illustrates how to use the string::operator+ STL function in Visual C++.


template<class _E, class _TYPE, class _A> inline
   basic_string<_E, _TYPE, _A>
   operator+( 
      const basic_string<_E, _TYPE, _A>& LString,
      const _E *RCharArray 
   );
template<class _E, class _TYPE, class _A> inline
   basic_string<_E, _TYPE, _A>
   operator+( 
      const _E *LCharArray,
      const basic_string<_E, _TYPE, _A>& RString 
   );
template<class _E, class _TYPE, class _A> inline
   basic_string<_E, _TYPE, _A>
   operator+( 
      const basic_string<_E, _TYPE, _A>& LString,
      const _E RChar 
   );
template<class _E, class _TYPE, class _A> inline
   basic_string<_E, _TYPE, _A>
   operator+( 
      const _E LChar,
      const basic_string<_E, _TYPE, _A>& RString 
   );
template<class _E, class _TYPE, class _A> inline
   basic_string<_E, _TYPE, _A>
   operator+( 
      const basic_string<_E, _TYPE, _A>& LString,
      const basic_string<_E, _TYPE, _A>& RString 
   );

NoteNote

The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

There are five versions of the string::operator+ function. Two functions are used to concatenate a null-terminated character array and a basic_string. Two functions are used to concatenate a character and a basic_string. The last function is used to concatenate two basic_string variables.

// StringPlus.cpp
// compile with: /EHsc
// Illustrates how to use the operator+ to concatenate
// a null-terminated character array and a basic_string,
// how to concatenate a character and a basic_string,
// and how to concatenate two basic_string variables.
//
// Functions:
//
//    operator+ : Concatenates a null-terminated character array and
//                a basic_string.
//    operator+ : Concatenates a character array and a basic_string.
//    operator+ : Concatenates two basic_string variables.
//////////////////////////////////////////////////////////////////////

#pragma warning(disable:4786)
#include <string>
#include <iostream>

using namespace std ;

int main()
{
   string result;
   string S1="ABC";
   string S2="DEF";
   char CP1[]="GHI";
   char C='J';

   cout << "S1 is " << S1 << endl;
   cout << "S2 is " << S2 << endl;
   cout << "CP1 is " << CP1 << endl;
   cout << "C is " << C << endl;

   result=S1+CP1;                           // Function 1  (ABCGHI)
   cout << "S1+CP1 is " << result << endl;

   result=CP1+S1;                           // Function 2  (GHIABC)
   cout << "CP1+S1 is " << result << endl;

   result=S1+S2;                            // Function 3  (ABCDEF)
   cout << "S1+S2 is " << result << endl;

   result=S1+C;                             // Function 4  (ABCJ)
   cout << "S1+C is " << result << endl;

   result=C+S1;                             // Function 5  (JABC)
   cout << "C+S1 is " << result << endl;
}

Output

S1 is ABC
S2 is DEF
CP1 is GHI
C is J
S1+CP1 is ABCGHI
CP1+S1 is GHIABC
S1+S2 is ABCDEF
S1+C is ABCJ
C+S1 is JABC

Header: <string>

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