The Boolean Logical Data Type

A logical variable can have only the value True or False. The keywords True and False are often implied thus the expressions 

You can use other data types as Boolean variables. When a variable is used in a logical expression, zero is converted to False while any non-zero value is converted to True. Thus the expression 

When Boolean variables are converted to other data types. False becomes zero but True is converted to -1. 

If j Then expression tests for a non-zero value of the variable j. 

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