Variable initialization --C ++ 11 (a)

Double D = 2.3 ;                // general initialization routine assignment 
Double D2 = { 2.3 }; 
conmplex < Double > Z { 1.2 , 2.1 }; // best mode, versatility 
Vector < int > {VEC . 1 , 2 , . 3 };        // initialize an array vessel or 
Auto I = 123 ;                  // Auto using this form 
int & {I} R & lt;                     // initialization of reference