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  00010 let result = ( 2 < 5 ) ! 2 < 5 evaluates to true, which is 1 in BR
  00010 let result = ~( 2 > 5 ) ! 2 > 5 evaluates to false, so ~( 2 > 5 ) evaluates to true, which is 1 in BR
  00020 print result           ! since result is 1, that's what will print on the screen
  00020 print result           ! since result is 1, that's what will print on the screen


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Revision as of 14:40, 9 January 2012

The logical unary negation operator ~ reverses the meaning of its operand. The operand must be numeric. Note that in BR, 1 means true and 0 means false.

The ~ operator works as follows:

  • The result is true if the operand is false
  • The result is false if the operand is true.

The ~ operator is equivalent to the NOT operator, with one difference: ~ works everywhere whereas NOT will only work in If and PRINT statements

~ is usually used in conjunction with an If statement.

The following examples demonstrates the use of ~:

00010 let x =  1 ! same as true
00020 let y = ~x ! not true evaluates to false, which is 0 in BR


00010 let result = ~( 2 > 5 ) ! 2 > 5 evaluates to false, so ~( 2 > 5 ) evaluates to true, which is 1 in BR
00020 print result            ! since result is 1, that's what will print on the screen