Decision points

IF amount>1000 THEN

assess by supervisor

IF not in stock THEN

order

IF number of books > 8 OR sum ≥ 100 THEN extra

discount

A decision point is a a combination of one or more conditions

that define the conditions for the various possibilities in the

subsequent system behaviour.

IF number of books > 8 THEN extra

discount

IF number of books > 8 THEN extra

discount

Test situations

Number of books

Result

Test situations 1 2

Number of books >8 ≤8

Result true false

IF number of books > 8 THEN extra

discount

Singular conditions lead to 2 test situations

Test situations 1 2

Number of books >8 ≤8

Result 1 0

IF number of books > 8 THEN extra

discount

In Boolean algebra a “1” is used to represent “true”

Test situations 1 2

Number of books >8 ≤8

Result 1 0

IF number of books > 8 THEN extra

discount

In Boolean algebra a “0” is used to represent “false”

Decision points may consist of a combination of

conditions

IF number of books > 8

ORsum ≥ 100 THEN extra

discount

IF number of books > 8THEN extra

discount

A B

IF number of books > 8 OR sum ≥ 100 THEN extra discount

IF number of books > 8 OR sum ≥ 100 THEN extra discount

Abbreviated notation

A OR B

IF number of books > 8 AND sum ≥ 100 THEN extra discount

IF number of books > 8 OR sum ≥ 100 THEN extra discount

Abbreviated notation

A OR B

Abbreviated notation

A AND B

Complete

decision table

A B

1 1

1 0

0 1

0 0

Based on two conditions we get these possible

combinations

A B

1 1

1 0

0 1

0 0

The end result depends on the operators AND and OR

Truth table

A B A OR B

1 1 1

1 0 1

0 1 1

0 0 0With the operator OR the end

result is ONLY false when both conditions are false

This table shows the outcome of all situations of a full

decision tale. Such a table is called a truth table.

Truth table

A B A AND B

1 1 1

1 0 0

0 1 0

0 0 0

Truth table

A B A OR B

1 1 1

1 0 1

0 1 1

0 0 0

With the operator AND the end result is ONLY true when

both conditions are false

Truth table

A B C (A AND B) OR C

1 1 1 1

1 1 0 1

1 0 1 1

1 0 0 0

0 1 1 1

0 1 0 0

0 0 1 1

0 0 0 0

A combined decisionthere may be different operators. When there are no brackets

AND proceeds OR