B4P Reference

Function Names

exchange

Description

This function exchanges the contents betweeen two variables, one variable and one entry in the table, or between two table entries. Note: Regarding variables, only the value in the base variable will be exchanged. Member variables will not be touched

Call as: procedure

Restrictions

Indirect parameter passing is disabled

Parameter count

Parameters

No.	Type	Description
1 io	all types	Variable or table entry 1
2 io	all types	Variable or table entry 2

Examples

  a[] = Abel; a[Age] = 30;

  b[] = Beata; b[Age] = 31;



  exchange( a[], b[] );



  echo( "Using exchange(...): Only base variables are exchanged.");

  echo( "  a[]: ", a[], ", ", a[Age] );

  echo( "  b[]: ", b[], ", ", b[Age] );



  table initialize( t, { { Name, Age}, {Corinne, 32} } );



  exchange( a[],    [t:Name,1] );

  exchange( a[Age], [t:Age,1] );



  echo( new line, "Exchanged with table entry: ");

  echo( "table: ", [t:Name,1] );

  echo( "  a[]: ", a[], ", ", a[Age] );



  // In case you want to exchange base variables with their members, use transactions.



  a[] = Abel; a[Age] = 30;

  b[] = Beata; b[Age] = 31;



  a[] <=> b[];



  echo( new line, "Using transactions: Members are also exchanged");

  echo( "  a[]: ", a[], ", ", a[Age] );

  echo( "  b[]: ", b[], ", ", b[Age] );

Output

Using exchange(...): Only base variables are exchanged.
  a[]: Beata, 30
  b[]: Abel, 31

Exchanged with table entry: 
table: Beata
  a[]: Corinne, 32

Using transactions: Members are also exchanged
  a[]: Beata, 31
  b[]: Abel, 30

Try it yourself: Open LIB_Function_exchange.b4p in B4P_Examples.zip. Decompress before use.

exchange