!
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## !

! — Logical NOT operator.

## Description

Arithmetic operators perform operations of change-sign (negate), don't-change-sign, logical AND logical OR, add, subtract, multiply and divide. Note that a value or an expression may fall between two of these operators, either of which could take it as its left or right argument, as in

a + b * c.

In such cases three rules apply:

1. * and / bind to their neighbors more strongly than + and −. Thus the above expression is taken as

a + (b * c)

with * taking b and c and then + taking a and b * c.

2. + and − bind more strongly than &&, which in turn is stronger than ||:

a && b - c || d

is taken as

(a && (b - c)) || d

3. When both operators bind equally strongly, the operations are done left to right:

a - b - c

is taken as

(a - b) - c

Parentheses may be used as above to force particular groupings.

## Syntax

    ! a  (logical NOT; not audio-rate)

where the argument a may be further expressions.

## Examples

Here is an example of the Logical NOT operator. It uses the file opnot.csd.

Example 32. Example of the opnot opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

    <CsoundSynthesizer>
    <CsOptions>
    ; Select audio/midi flags here according to platform
    -odac    ;;;realtime audio out
    ;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
    ; For Non-realtime ouput leave only the line below:
    ; -o opand.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

    sr = 44100
    ksmps = 32
    nchnls = 2
    0dbfs  = 1

    instr 1

    kval    randomh 0, 1.2, 20		;choose between 0 and 1.2
    if !(kval >0 && kval<=.5) then		;3 possible outcomes
    	kval = 1
    elseif !(kval >.5 && kval<=1) then
    	kval =2
    elseif !(kval >1) then
    	kval =3
    endif

    printk2 kval				;print value when it changes
    asig    poscil .7, 440*kval, 1
            outs asig, asig

    endin
    </CsInstruments>
    <CsScore>
    f1 0 16384 10 1

    i 1 0 5
    e
    </CsScore>
    </CsoundSynthesizer>

Its output should include lines like these:

     i1     1.00000
     i1     2.00000
     i1     1.00000
     i1     2.00000
     i1     1.00000
     i1     2.00000
     i1     1.00000
    .....

## See also

Arithmetic and Logic Operations

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