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hi, i was going throught java exercise i did not get this exercise? if you know anything please post your comments here.
Which of the following applications may use a stack?
A. A parentheses balancing program.
B. Keeping track of local variables at run time.
C. Syntax analyzer for a compiler.
D. All of the above.
I'd say D.
I agree
The question is, do you know what a stck is? If not, then we can explain - then you will be able to answer the question all by yourself ;)Quote:
Originally Posted by indianj
thanks for your answer. yes i do not stack now.
You have a large number of presents and you put them together, you put one present on top of the other. This is a stack. If you try to take one of the presents form the middle of the stack, all the others will fall. So you can only take something off the top of the stack.
A stack is referred to as a LIFO (Last in First Out) - and they are used often in programming. For example, in a program you have a calling stack, each time you call a function, a pointer is pushed (placed) on the calling stack, once the current function has finished executing, the last item on the called stack is popped (taken off) and execution resumes form the next statement in the calling function. Once the stack is empty and the current execution has finished the program ends.
Another implementation of stacks is Reverse Polish notation, whereby a mathematical expression is represented by string. All numbers are pushed on to the stack and operators cause two numbers to be popped from the stack and a portion of the expression to be solved. Calculators and computers use these.
So, to work out where a stack might be used think of situation where you need to store a set of data but only ever require/want the last item you put inside the store. If we use Java as an example and apply it to this statement:
In Java locals variables mask variables of the same name which are member of the current class. Each block in which a variable is declared masks the higher scope. So it would be sensible to assume that like the calling stack, a variable stack exists too.Quote:
B. Keeping track of local variables at run time.
just say B for god's sake
I would use stacks in C too. especially when you are analyzing syntax which is likely to be nested. I.e: nested loops and if statements.
I still keep with D since I have tried all the first 3 choices and implemented them all using a stack. heck its even in the compiler book to use a stack. :s
I still agree with you ocean
A. was in the Data structure book.
B. was an example in system architecture book.
C. was in the compiler book.
thanks ;)Quote:
Originally Posted by ComputerJy