Question

How to define a char stack in java? For example, to create a String stack I can use such construction:

Stack <String> stack= new Stack <String> ();

But when I’m try to put char instead String I got an error:

Syntax error on token "char", Dimensions expected after this token

Answer 1

Using a collection of char is pretty inefficient. (but it works) You could wrap a StringBuilder which is also a mutable collection of char.

class CharStack {
    final StringBuilder sb = new StringBuilder();

    public void push(char ch) {
        sb.append(ch);
    }

    public char pop() {
        int last = sb.length() -1;
        char ch= sb.charAt(last);
        sb.setLength(last);
        return ch;
    }

    public int size() {
        return sb.length();
    }
}