Editing Csound (section)

== Csound code ==
Csound takes two specially formatted [[text file]]s as input. The ''orchestra'' describes the nature of the instruments and the ''score'' describes notes and other parameters along a timeline. Csound processes the instructions in these files and renders an [[audio file]] or real-time audio stream as output.

The ''orchestra'' and ''score'' files may be unified into a single structured file using [[markup language]] tags (a CSD file with [[filename extension]] .csd). Here is a very simple example of a unified Csound data file which produces a [[wave file]] containing a one-second [[sine wave]] tone of 1 [[Kilohertz|kHz]] at a [[Sampling frequency|sample rate]] of 96&nbsp;kHz:

<syntaxhighlight lang="csound-csd">
<CsoundSynthesizer>
  
  <CsOptions>
    csound -W -d -o tone.wav
  </CsOptions>
  
  <CsInstruments>
    sr     = 96000           ; Sample rate.
    kr     = 9600            ; Control signal rate.
    ksmps  = 10              ; Samples per control signal.
    nchnls = 1               ; Number of output channels.

    instr 1
    a1     oscil p4, p5, 1   ; Oscillator: p4 and p5 are the arguments from the score, 1 is the table number.
    out a1                   ; Output.
    endin
  </CsInstruments>

  <CsScore>
    f1 0 8192 10 1           ; Table containing a sine wave. Built-in generator 10 produces a sum of sinusoids, here only one.
    i1 0 1 20000 1000        ; Play one second of one kHz at amplitude 20000.
    e
  </CsScore>

</CsoundSynthesizer>
</syntaxhighlight>
As with many other programming languages, writing long programs in Csound can be eased by using an [[integrated development environment]] for editing, previewing, testing, and [[debugging]]. The one now officially supported is CsoundQt. It has many features, such as automatic code insertion, integrated documentation browser, integrated widgets for graphically controlling parameters in realtime, plus a button for playing the code.