write output of the segment of program below

10 A$ = "ONE O"
20 B$ = "ONE "
30 D$ = " "
40 C$ = A$ & D$ & B$
50 PRINT C$

what, you don't have a BASIC interpreter to run that through?

& just means to join the strings together...

have no system for now. it was damage weeks ago

pls any website to run this online, i had problem with my system

You must not have tried very hard to find a web site.

google will show you many online basic interpreters, such as this one

http://www.quitebasic.com/prj/basics/strings/

However, they may not run your program as-is. The original BASIC used LET statements to make assignments. The above interpreter will run your program, if it is modified as below:

10 Let A$ = "ONE O"
20 Let B$ = "ONE "
30 Let D$ = " "
40 let C$ = A$ + D$ + B$
50 PRINT C$

To determine the output of this program, we need to follow the sequence of instructions step by step:

1. Line 10 assigns the value "ONE O" to a string variable named A$.
2. Line 20 assigns the value "ONE " to another string variable named B$.
3. Line 30 assigns an empty string (space) to a string variable named D$.
4. Line 40 concatenates the values of A$, D$, and B$ together and assigns the result to a string variable named C$. The resulting string would be "ONE O ONE ".
5. Line 50 prints the value stored in variable C$, so the output of the program would be "ONE O ONE ".

Therefore, the output of this segment of code would be:
ONE O ONE