Thread: Stack - For loop not returning proper result

Below is a method that is suppose to insert a value inside a stack based on the index. I thought it would be easier to copy the value, if any, that was in the index into the variable holder and replace it with the input value. After in which it would copy the holder value and place it at the top of the stack. (topOfStack variable is what the holder is copying too.)

public void pushExact (int index, String input) {
	String holder = "";
	if (maxSize == 0) {
		theStack[topOfStack] = input;
		topOfStack++;
	} else if (topOfStack + 1 < maxSize) { 
		for (int n= maxSize - 1;n >= 0;n--) {
			if (n == index) { //this isn't returning the proper result. Its taking the topOfStack and not factoring in the index. 
				holder = theStack[topOfStack];
				System.out.println("Holders" + " value is: " + holder);
				theStack[topOfStack] = input;
				}
			}
			theStack[topOfStack] = holder; 
			System.out.println("bottom is: " + bottom);
			System.out.println("topOfStack is: " + topOfStack);
			topOfStack++;	
	} else {
		System.out.println("The Stack is full.");
	}
	display();
}

Originally Posted by Johnathanrs

Below is a method that is suppose to insert a value inside a stack based on the index.

That does not make any sense whatsoever.
The idea of a stack is that you cant insert values at random locations.
With your method your data structure would no longer be a stack, so please clarify.

You're describing a List, perhaps a linked list. Stacks and queues are data structures that do not insert elements in their middles.

@Cornix
Self-learning. I started off trying to learn what a stack is and diverged on my own path from the core lessons taught. Not focusing on terminology or what it is technically called at this point. Just trying to learn how to create random functions from top of my head. Forget that I called it a stack. What is exactly wrong with my method?

@Greg
I am learning about linked list atm, but I believe what my method is doing is slightly different, but theoretically similar to the concept to a linked list. However, I am not shifting elements, but swapping the index point, storing it in a random variable, and than swapping the random variable with the first or last element. My next task is to figure out how to shift every element over by one, but I am not at that point yet in my learning.

Interesting exercises. Good luck.

The inside of your for-loop does not make any sense at all to me. Could you perhaps make a comment about every single line and tell us exactly what you are trying to do and what your idea was?

			if (n == index) { //this isn't returning the proper result. Its taking the topOfStack and not factoring in the index. 
				holder = theStack[topOfStack];
				System.out.println("Holders" + " value is: " + holder);
				theStack[topOfStack] = input;
				}
			}
			theStack[topOfStack] = holder; 
			System.out.println("bottom is: " + bottom);
			System.out.println("topOfStack is: " + topOfStack);
			topOfStack++;