/* bsearch.pl0 */

type Arr = array[0..9] of integer; /* typedef an array */
var a: Arr; /* define a global variable */

/*
** Find value in [first, last).
** If found, return its index; otherwise return last index.
*/
function bsearch(first: integer; last: integer; value: integer): integer;
var i: integer; /* define local variables */
    ret: integer;
begin
    ret := last;
    while (first < last) do begin
        i := first + (last - first) div 2;
        if (a[i] = value) then begin
            bsearch := i;   /* similar to return */
        end else if (a[i] < value) then begin
            first := i + 1;
        end else begin
            last := i;
        end;
    end;

    bsearch := ret;
end;

/* main() */
begin
    a[0] := -3;
    a[1] := -2;
    a[2] := 0;
    a[3] := 1;
    a[4] := 1;
    a[5] := 7;
    a[6] := 8;
    a[7] := 11;
    a[8] := 22;
    a[9] := 27;

    write(bsearch(0, 10, 22));  /* 8 */
    write(bsearch(0, 10, -1));  /* 10 */
end.