From QB64.org wiki
A colon can be used to separate two unrelated procedure statements on the same line.
Usage: COLOR 10: PRINT "Hello "; : COLOR 12: PRINT "World"
- Use colons to combine variable definition statements or screen prints.
- Some statements such as END IF and Metacommands require a new code line!
- Use semicolons and commas where appropriate in PRINTs.
- Use an underscore at the end of a line to extend a line of code to the next line.