DaniWeb Forum Index > Software Development > C++

Help with Queues and Stacks please

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Aug 2009

Posts: 27

Reputation: scantraXx- has a little shameless behaviour in the past

Solved Threads: 0

scantraXx- scantraXx- is offline

Offline

Light Poster

Help with Queues and Stacks please

Oct 5th, 2009

Hey guys.

I need help with these questions please

1. Write a function that takes as a parameter a queue of integers and returns a copy of the queue with all the elements stored in reverse order. Use a stack as a helper data structure.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
queue<int> reverseQueue(queue<int> q)
// pre: none
// post: returns a queue with the elements stored in reverse order
queue<int> reverseQueue(queue<int> q)
// pre: none
// post: returns a queue with the elements stored in reverse order

For example, after creating a queue in the following way and calling the function:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 queue<int> myQueue, rQueue;
      myQueue.push(1);
      myQueue.push(2);
      myQueue.push(3);
      rQueue = reverseQueue(myQueue);
 queue<int> myQueue, rQueue;
      myQueue.push(1);
      myQueue.push(2);
      myQueue.push(3);
      rQueue = reverseQueue(myQueue);

then the resulting rQueue has 1 at the back, 2 in the middle, and 3 at the front.

2. Write a function that reverses a string by making use of a stack. Your function could push elements on the stack one by one, and then build up the result by popping them off the stack.

Help with Code Tags

C++ Syntax (Toggle Plain Text)

 string reverseString(string s)

Any help would be appreciated.

Thanks

•

Join Date: Sep 2009

Posts: 358

Reputation: dkalita will become famous soon enough

Solved Threads: 56

dkalita

Offline

Posting Whiz

Re: Help with Queues and Stacks please

Oct 5th, 2009

prob 1.

Remove all the elements of the queue and push it in the stack.
Now pop from the stack one element at a time and add it to the new queue until the stack is empty. Now return the new queue.

prob 2.

the answer is there in your question itself. Just do as its said.

***IMP : Dont expect readymade code in here.
If u want them then u r in the wrong place.

•

Join Date: Nov 2008

Posts: 467

Reputation: Grn Xtrm will become famous soon enough

Solved Threads: 39

Grn Xtrm

Offline

Posting Pro in Training

Re: Help with Queues and Stacks please

Oct 5th, 2009

•

Originally Posted by scantraXx-

2. Write a function that reverses a string by making use of a stack. Your function could push elements on the stack one by one, and then build up the result by popping them off the stack.

Use the push function to add each element of the string onto the stack, then use the pop function to remove each element. You can print each value after popping, then move onto the next element until the stack is empty.

Check out my new band URL on facebook. I'm the bass player. :) Become a fan and leave comments if you like.
URL on facebook!