Problem 5 

Implement the move features: 

• List( List&& aOtherList ), 

• List& operator=( List&& aOtherList ), 

• void push_front( T&& aElement ), 

• void push_back( T&& aElement ). 

The move features “steal” the memory of the argument. That is, calling the copy constructor  or using the assignment operator leaves aOtherList empty. Similarly, calling  push_front() and push_back(), respectively, leaves aElement empty.  

The move variants are chosen be the compiler if the argument is a temporary or literal  expression. 

To force move semantics we have to use, where necessary, the std::move() function,  which performs a type conversion on its argument that guarantees that the argument is an r value reference. 

You can use #define P5 in Main.cpp to enable the corresponding test driver. 

void testP5() 

{ 

 using StringList = List<string>; 

 string s2( "CCCC" );   

 List<string> lList; 

 cout << "Test of problem 5:" << endl; 

 lList.push_front( string( "DDDD" ) ); 

 lList.push_front( std::move(s2) ); 

 lList.push_front( "BBBB" );   

 if ( s2.empty() ) 

 { 

 cout << "Successfully performed move operation." << endl; 

 } 

 else 

 { 

 cerr << "Error: Move operation failed." << endl; 

 }   

 cout << "A - Top to bottom " << lList.size() << " elements:" << endl; 

 for ( const string& element : lList ) 

 { 

 cout << element << endl; 

 }   

 List<string> move( std::move(lList) ); 

 if ( lList.empty() ) 

 { 

 cout << "Successfully performed move operation." << endl; 

 } 

 else 

 { 

 cerr << "Error: Move operation failed." << endl; 

 } 

 // iterate from the top 

 cout << "B - Top to bottom " << move.size() << " elements:" << endl;  

 for ( const string& element : move ) 

 { 

 cout << element << endl; 

 } 

 // override list 

 lList = std::move(move);   

 if ( move.empty() ) 

 { 

 cout << "Successfully performed move operation." << endl;  } 

 else 

 { 

 cerr << "Error: Move operation failed." << endl; 

 } 

 lList.push_front( "AAAA" ); 

 lList.push_back( "EEEE" ); 

 // iterate from the top 

 cout << "C - Bottom to top " << lList.size() << " elements:" << endl;   

 for ( auto iter = lList.rbegin(); iter != iter.rend(); iter-- )  { 

 cout << *iter << endl; 

 }  

 cout << "Completed" << endl; 

} 

The result should look like this: 

Test of problem 5: 

Successfully performed move operation. 

A - Top to bottom 3 elements: 

BBBB 

CCCC 

DDDD 

Successfully performed move operation. 

B - Top to bottom 3 elements: 

BBBB 

CCCC 

DDDD 

Successfully performed move operation. 

C - Bottom to top 5 elements: 

EEEE 

DDDD 

CCCC 

BBBB 

AAAA 

Completed

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