for-in loop

What is translated > Statements > for loop's > for-in loop

for-in loops are a special kind of Delphi for-loops which have the syntax:

var

  a : typename;

begin

for a in B do

  DoSomething(a);

where 'a' may be a character in a string 'B' or  'a' may be an element of an array 'B' or  'a' may be a member of a set 'B'. These cases mostly are translated to a C++11 range-based for loop:

typename a;

for (typename element_0 : B)

{

  a = element_0;

  DoSomething(a);

}

For C++Builder, in the special case, that 'B' is an open array, a cast is necessary. That may for example look like:

void __fastcall ArrayOfConstLoop(const T* B, int B_maxidx)

{

  T a;

  for(auto element_0 : *(T(*)[B_maxidx])B)

  {

    a = element_0;

    DoSomething(a);

  }

}

The necessary iterators for sets and open arrays are defined in d2c_systypes.h.

For container types that implement a GetEnumerator() method the for loop looks like:

       while(B->GetEnumerator()->MoveNext())

       { 

               T a = B->GetEnumerator()->Current

               DoSomething(a);

       }

This page belongs to the Delphi2Cpp Documentation