Аутентификация пользователя (Pascal -> C)

var a,b,c,pass,found:string;
 
procedure wwords();
begin
writeln('Write 3 words:');
repeat
readln(a);
if a='' then writeln('ERROR.Try again');
until (a<>'');//1
repeat
readln(b);
if b='' then writeln('ERROR.Try again');
until (b<>'');//2
repeat
readln(c);
if c='' then writeln('ERROR.Try again');
until (c<>'');//3
end;
 
procedure fpass();
begin
found:='';
if c[1]='z' then begin found:=found+'a'; end
else begin found:=found+succ(c[1]); end;//1
if b[1]='a' then begin found:=found+'z'; end
else begin found:=found+pred(b[1]); end;//2
if length(c) mod 2 =1 then begin
if c[(length(c)+1) div 2]='z' then begin found:=found+'a'; end
else begin found:=found+succ(c[(length(c)+1) div 2]); end
end
else begin
if c[length(c) div 2]='a' then found:=found+'z'
else found:=found+pred(c[length(c) div 2]);
end;//3
if (length(a)+length(b)-2>0) then begin 
found:=found+chr(97+((length(a)+length(b)-2-1) mod 26));
end; //4
writeln('Pass:',found);
end;
 
procedure wpass();
begin
writeln('Enter Password:');
readln(pass);
 
if pass=found then writeln('Pass is correct!')
else writeln('Pass is wrong!');
end;
 
begin
wwords;
fpass;
wpass;
end.