BEGIN

INTEGER I, K, NFOUND;
INTEGER ARRAY FACTORS[1:16];

COMMENT - RETURN P MOD Q;
INTEGER FUNCTION MOD (P, Q);
INTEGER P, Q;
BEGIN
    MOD := P - Q * (P / Q);
END;

COMMENT
  FIND THE PRIME FACTORS OF N AND STORE IN THE EXTERNAL
  ARRAY "FACTORS", RETURNING THE NUMBER FOUND. IF N IS
  PRIME, IT WILL BE STORED AS THE FIRST AND ONLY FACTOR;

INTEGER FUNCTION PRIMEFACTORS(N);
INTEGER N;
BEGIN
  INTEGER P, COUNT;
  P := 2;
  COUNT := 1;
  WHILE N >= P * P DO
    BEGIN
      IF MOD(N, P) = 0 THEN
        BEGIN
          FACTORS[COUNT] := P;
          COUNT := COUNT + 1;
          N := N / P;
        END
      ELSE
        P := P + 1;
    END;
  FACTORS[COUNT] := N;
  PRIMEFACTORS := COUNT;
END;

COMMENT -- EXERCISE THE ROUTINE;

FOR I := 77 STEP 2 UNTIL 99 DO
  BEGIN
    WRITE(I,":");
    NFOUND := PRIMEFACTORS(I);
    COMMENT - PRINT OUT THE FACTORS THAT WERE FOUND;
    FOR K := 1 STEP 1 UNTIL NFOUND DO
      BEGIN
        WRITEON(FACTORS[K]);
      END;
  END;

END