you can use SE80, SE38 to create/modify and view a program
and sa38 to view a program.
But Regarding the modes ABAP/4 Editor have Three Modes
1. Front-End Editor -source code mode - new
2· Front-End Editor -plain text mode - old
3· Back-End Editor -line-based mode
The three editor modes are fully compatible and interchangeable. Source code created using one mode is properly displayed by the system in all other modes.
The Source Code Mode of the Front-End Editor offers enhanced functionality over the Plain Text Mode by allowing syntax highlighting, collapsing and expanding language blocks, code templates, code completion and so on.
Please reward points if it helps