Determine whether the length of an array is length or sizeof?

Recently I found some Code And even some expert code, the length of the array used when traversing the array turns out to be sizeof (ARR); this is not suitable!

If it is a one-dimensional array and the element size is a byte, no error is displayed, for example:

 
VaR arr1: array [0 .. 9] of char; arr2: array [0 .. 9] of byte; begin showmessagefmt ('% d, % d', [length (arr1), sizeof (arr1), length (arr2 ), sizeof (arr2)]); {display result: 10, 10, 10} end;

  
 

However, if the array element contains more than one byte or multi-dimensional array, it will not work. For example:

Const arr1: array [0 .. 9] of integer = (,); arr2: array [0 .. 1, 0 .. 3] of integer = (1, 2, 3, 4), (5, 6, 7, 8); var arr3: array [Boolean] of integer; arr4: array [byte] of integer; begin showmessage (inttostr (length (arr1); {10} showmessage (inttostr (sizeof (arr1); {40} showmessage (inttostr (length (arr2 ))); {2} showmessage (inttostr (length (arr2 [0]); {4} showmessage (inttostr (length (arr2 [1]); {4} showmessage (inttostr (sizeof (arr2); {32} showmessage (inttostr (length (arr3 ))); {2} showmessage (inttostr (sizeof (arr3); {8} showmessage (inttostr (length (arr4 ))); {256} showmessage (inttostr (sizeof (arr4); {1024} end;

  
 

We can use this principle to quickly know the total number of elements in a multi-dimensional array:

 const arr: array [0 .. 1, 0 .. 2, 0 .. 3] of integer = ), (6, 6, 6); begin showmessage (inttostr (sizeof (ARR) Div sizeof (integer); {24} end;