% — Modulus operator.

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.

The operator *%* returns the value of *a* reduced by *b*, so that the result, in absolute value, is less than the absolute value of *b*, by repeated subtraction. This is technically a remainder, like the % operator in C and similar languages, and not actually a modulus. New in Csound version 3.50.

The arguments of % can be scalar values or k-rate one dimensional arrays (vectors), or any combination. If one of the arguments is an array, so is the value.

Here is an example of the % operator. It uses the file *modulus.csd*.

**Example 18. Example of the % operator.**

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 -Ma --midi-key=4 --midi-velocity-amp=5 -m0 ;;;realtime audio out and midi in ;-iadc ;;;uncomment -iadc if realtime audio input is needed too ; For Non-realtime ouput leave only the line below: ; -o %.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 giScale ftgen 1, 0, -12, -2, 0, -34, -7, 10, -14, 3, -21, -3, -27, -10, 7, -17 ;12 note scale with detuned keys instr 1 ikey = p4 ivel = p5 indx = ikey % 12 ;work on the twelftone scale icent tab_i indx, giScale ;load the scale ifreqeq = cpsmidinn(ikey) ifreq = ifreqeq * cent(icent) ;change frequency by cents from table prints "Key %d modulus 12 = %d. ", ikey, indx prints "Equal-tempered frequency of this key = %f,", ifreqeq prints " but here with cent deviation %d = %f%n", icent, ifreq asig vco2 ivel*.5, ifreq outs asig, asig endin </CsInstruments> <CsScore> f 0 60 ;run for 60 seconds e </CsScore> </CsoundSynthesizer>