Help on understanding this code

hi everyone i'm beginner in delphi language and i need to understand this code :
repeat
s4:= UpperCase(Edit1.Text[4]);
X:=0;
for i := 1 to 3 do
s4:= s4 + chr(Random(25)+$41);
for i := 1 to Length(s4) do
x:= x + Ord(s4[i]);
x:= x mod $28;
until x = $14;

so please any one explaine for me this code

Hello,

First of all make sure you know what every part of the code means, never try to read chunks of code in it's entirety. For more info, here's a handy site I regularly consult - Delphibasics .

Having said that, here's basically what your code does:

You've got a variable x (I'm assuming integer, you didn't specify), which has a certain value. The piece marked (code) will be run at least once, after which x will be checked. If it's equal to $14 (which is the hexadecimal notation for 20), you've reached the end of the loop. If not, the part in between repeat and until will be ran again, until X equals 20.

s4 is a String, Edit1 is a component (probably of type TEdit) on a form. Here, the 4th character of the string currently in your editbox (Edit1) will be converted to uppercase, and stored in String s4; if you typed in the word "example" without quotes in the editbox, you'd end up with "M" (again, without quotes) in s4.
The integer value X will be set to zero.

This loop will add three letters after the character already in s4 (the for loop runs with i = 1, i = 2, i = 3).
Random(25) gives you a value ranging from 0 to 25, after which $41 (or 65 in decimal) is added. Remember that 65 is Ascii for capital letter A.
So far you have an integer, so Chr(x) converts an integer to a character, after which you add it to the already existing String s4.
By now s4 should read something like MTFE (random).

s4 has a Length of 4 characters by now, and x was 0 until now. So for each letter in the String s4, add the ordinal value of said latter to x.
With the example above, x will increase with the ordinal value of M, T, F and E (77, 84, 70 and 69 respectively).

Mod performs an integer division, and returns the remainder. So here you divide x by $28 (decimal 40), and assign the remainder of the division back to x.

As mentioned before, this will repeat until x becomes 20.

Hope this helps - as far as the purpose of this particular code goes, I'll leave that one up to you.

Best regards,

Marlon