c++ - No conversion from long unsigned int to long unsigned int& -

I get an error message for <2> long code unsigned int No known conversion when I try to compile the following code, then long unsigned integer :

  zero creation (int * and array, unsigned Long and index) {if (index == 0) return; Other {hepiv (array, index); Construction (array, index-1); }}   
 Does anyone explain why this happens, and what is the logic behind this error? The second argument of  
 
  build  is a reference ( & amp; / Code> is marked with). A reference is like an indicator, so you can only use a real variable in which memory is known.  
 This is the reason that you can not use an expression like  index-1 .