I'm trying to create a 'history' kind of feature that follows the LIFO characteristics. Last Input First Output.
So the user will introduce some words that will be stored in a stack for printing them afterwords. The program, summarized, looks like this:
Stack<String> history = new Stack<>();
String word = null;
while (!word.equals(exit)) {
word = scan.nextLine();
if (word.equals(show)) {
showHistory();
} else {
history.push(word);
}
}
And showHistory(); function have this format:
for (String i : history) {
System.out.println(i);
}
The issue is, when I execute this, the output I get it's the words the user might have introduced but in a FIFO format. For example, if the user introduces:
Pencil
Book
Shirt
The output this program shows is:
Pencil
Book
Shirt
But the output I want, following the LIFO format is:
Shirt
Book
Pencil
I also don't want to delete the data the stack is storing in any point of the execution, so I don't want to use history.pop(); because, if I'm not wrong, that would delete the data in the stack.
How can I do this?
Thanks in advance.
For this you yould create a helper stack which can hold the popped items temporarily:
Stack<String> temp = new Stack<>();
while(!history.isEmpty()){
System.out.println(history.peek());
temp.push(history.pop);
}
while(!temp.isEmtpy){
history.push(temp.pop);
}