Need help with a program i've been trying to make

[guest58006]

So I know this program IS simple, but I am still a beginner and it would be nice for someone to help me find the mistake and maybe even fix it myself so I should know how to avoid it in the future.
Basically what I'm trying to create is a simple program calculating how much money you will have after depositing your money for a certain period of time at a certain bank rate. The only condition it being that I cannot leave it after the sum doubled itself. I'm trying to do it as simple as possible, and also only use repeat until/while/for/etc.
Here's the program:

Code: Pascal  [Select][+][-]

1. program bank;
2. var
3.   k,n : real;
4.   a : integer;
5. begin
6. writeln ('Introduce the annual rate');
7. readln (k);
8. writeln ('Introduce the initial sum');
9. readln (n);
10. writeln ('Introduce the number of years');
11. readln (a);
12. while n <= 2*n do
13. begin
14. n:= n+(k*n)/100;
15. a:= a+1;
16. writeln (a, '  ',n:0:5);
17. end;
18. writeln ('Press ENTER to continue...');
19. readln;
20. end.

EDIT: Forgot to add that I always get error 205, and the program runs properly, but after adding all the values in, it goes through a massive amount of text and just stops.

[balazsszekely]

You force your program into a runaway loop. The initial condition is n < 2*n then you increase n, so the condition is never met.
It's similar to:

Code: Pascal  [Select][+][-]

1. while 1 < 2 do
2. begin
3.   //do something
4. end;

Try this instead:

Code: Pascal  [Select][+][-]

1.  m := 2*n;
2.  while n <= m do
3.  begin
4.    //...
5.  end;                
6.  

[guest58006]

Actually I HAD m in my program at the start, but thought that too many variables wouldn't be that great. Will try and then reply again.

[guest58006]

You force your program into a runaway loop. The initial condition is n < 2*n then you increase n, so the condition is never met.
It's similar to:

Code: Pascal  [Select][+][-]

1. while 1 < 2 do
2. begin
3.   //do something
4. end;

Try this instead:

Code: Pascal  [Select][+][-]

1.  m := 2*n;
2.  while n <= m do
3.  begin
4.    //...
5.  end;                
6.  

OK, this has helped me. But as an answer I get the number AND the decimals. I thought 0:5 should've removed them? Am I doing something wrong? What is the actual way to remove the decimal part of a real number? (Sorry for these questions but we're going fast through all the subjects and sometimes I find it relatively hard to understand everything.

[balazsszekely]

@aerowei
What is the actual way to remove the decimal part of a real number?

Use the function Trunc(http://www.freepascal.org/docs-html/rtl/system/trunc.html)