Editing BlooP and FlooP (section)

=== Subtraction function ===
This is not a built-in operation and (being defined on natural numbers) never gives a negative result (e.g. 2 &minus; 3 := 0). Note that <code>OUTPUT</code> starts at 0, like all the <code>CELL</code>s, and therefore requires no initialization.

{{pre|1=
DEFINE PROCEDURE ''MINUS'' [M,N]:
BLOCK 0: BEGIN
        IF M < N, THEN:
        QUIT BLOCK 0;
        LOOP AT MOST M + 1 TIMES:
        BLOCK 1: BEGIN
                IF OUTPUT + N = M, THEN:
                ABORT LOOP 1;
                OUTPUT ⇐ OUTPUT + 1;
        BLOCK 1: END;
BLOCK 0: END.
}}