Can a global variable be a local variable as well?

 
I have a local variable called last_accessed and i use it in the global scope inside the EA. But now i want to use it as a global variable. Do i need to create another name for it or can i just access it with the same name e.g. GlobalVariableGet("last_accessed"). Also, how does the strategy tester deal with global variables? Does it set them as well and hence interfere with the live values? I hope my question was clear enough, if it is not, i'd be happy to elaborate.

thanks in advance
 
For using Global Variables you don't must to definite it. Global variable ("MQL4: Global variables") and local variables are different even if have identical names.