Pascal : fatal syntax error - pascal

Question

Trying to execute catalan numbers in Pascal but getting fatal syntax error.
Error is :
Fatal: Syntax error, ";" expected but "identifier B" found
Error: /usr/bin/ppcx64 returned an error exitcode
Here is ref code
program main;
var
i,buf: integer;
function catalan(num: integer): integer;
var
sample, returnval : integer;
function bincoeff(n: integer): integer;
var
a,b,retval,numr,denom1,denom2: integer;
bc : integer;
function fact(x: integer): integer;
begin
// fact exec
if x=0 then
fact :=1
else
fact := x* fact(x-1);
end;
begin
//bincoeff exec
a := 2*n
b := n
if a==b then
retval :=1
else if b>a
retval :=0
else
numr := fact(a)
denom1 := fact(b)
denom2 := fact(a-b)
bc := numr /(denom1*denom2)
retval := bc
end;
begin
// catalan exec
sample :=bincoeff(num)
returnval := (sample/(num+1))
end;
begin
for i :=0 to 9 do
begin
buf := catalan(i)
writeln(buf)
end;
end.

Answer 1

Starting with
a := 2*n
till the end of the program you systematically don't use ';'. A fact that, by the way, is signaled pretty clearly by the compiler.
In this context it might be interesting to visit the FreePascal wiki on the topic of the semicolon which points out an important difference between C and Pascal's usage of the semicolon (separator vs terminator). A must-read.