DDS is not a programming language. Instead, it is used to describe a virtual "display file" object - basically a green screen display template.
It describes display file "records" (regions of the screen, generally like a header, one or more lists, called subfiles, and footers and message areas.).
Within those records, you can describe constants and variable fields. You can also define file level, record level and field level keywords and function keys.
Once you finish coding your DDS, you "compile" it using CRTDSPF into a display file object that can be referenced by a HLL language program (CL, RPG, COBOL, or C usually in modern systems).
HLL languages have different mechanisms for using display files for screen I/O, but in general you populate the variable values in the display file "record", then WRITE the display file record (or records) which displays it onthe screen. You then READ the display file record to retrieve any variable values modified by the user. Some languages have a combine WRITE/READ operation (CL SNDRCVF, RPG EXFMT, etc).
Disply file programming is relatively complex. Post back if you need help finding documentation and examples.
It describes display file "records" (regions of the screen, generally like a header, one or more lists, called subfiles, and footers and message areas.).
Within those records, you can describe constants and variable fields. You can also define file level, record level and field level keywords and function keys.
Once you finish coding your DDS, you "compile" it using CRTDSPF into a display file object that can be referenced by a HLL language program (CL, RPG, COBOL, or C usually in modern systems).
HLL languages have different mechanisms for using display files for screen I/O, but in general you populate the variable values in the display file "record", then WRITE the display file record (or records) which displays it onthe screen. You then READ the display file record to retrieve any variable values modified by the user. Some languages have a combine WRITE/READ operation (CL SNDRCVF, RPG EXFMT, etc).
Disply file programming is relatively complex. Post back if you need help finding documentation and examples.