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Logical IF Example 1

This example demonstrates the use of the logical IF statement. Logical operations may be performed on numerical variables and/or constants.

$$
$$ Declarations
$$
    ENTITY/LN(3)
$$
$$ Geometry Definition
$$
    LN(1)=LINE/-1,0,1,0
    
    LN(2)=LINE/PARLEL,LN1,YLARGE,.5
    
    LN(3)=LINE/-1,-.5,1,.5
$$
$$ Do Statements
$$
    DO/A1:,I,1,3
    $$
    $$ Get the end points of the line
    $$
    OBTAIN/LN(I),X1,Y1,,X2,Y2,
    $$
    $$ If the line is not horizontal, ignore it
    $$
    IF/Y1<>Y2,JUMP/A1:
    $$
    $$ If the Y value is greater than zero, delete it
    $$
    IF/X1>0,DELETE/LN(I)
    A1:

In the example above only LN(2) would be deleted as LN(3) is not a horizontal line and LN(1) is coincident with the X axis.