// Implement your own stack, CharStack, using Linked list. // You shall not use the default Linked List class from Java. // Element in CharStack is CharNode which contain a char. public class CharStack { protected CharNode top; public CharStack() { top = null; } // Initialize a new CharStack with a char. // It means the stack will contain an element, a CharNode which carries the input char. public CharStack(char c) { // 1. Filling your code here // 1. End of code } // Initialize a new CharStack with a existing CharStack. It's copying the input CharStack and create a new one. // Hint: // Do not modify the input CharStack public CharStack(CharStack cs) { // 2. Filling your code here // 2. End of code } // Create a CharStack. The stack shall contain all the charactors in input string. // Hint // The last char in string shall be at the top of the stack. public CharStack(String str) { // 3. Filling your code here // 3. End of code } // push a char to the top of the stack public void push(char c) { // 4. Filling your code here // 4. End of code } // pop the top char from the stack // Hint // For you convenience, you are not required to handle exception when poping a empty stack. // It means when a stack is empty, do nothing. public void pop() { // 5. Filling your code here // 5. End of code } // return the char of the top element public char top() { // 6. Filling your code here // 6. End of code } // return true if the stack is empty, otherwise, return false; public boolean isEmpty() { // 7. Filling your code here // 7. End of code } // return the number of elements in the stack public int size(){ // 8. Filling your code here // 8. End of code } // transfer the stack to a string and return it. // E.g. From bottom to the top, if the chars in stack are 'a', 'e', 'c', '!'. The return shall be "aec!" public String toString() { // 9. Filling your code here // 9. End of code } }

public class CharNode { // Instead of implement a single function as before, You are required to design and implement the whole class. // Design and implement your CharNode. It's a link node which contains a char // You can define any attributes or methods on your own // You will use your CharNode class in CharStack. // 10. Filling your code here protected T info; protected CharNode link; public CharNode(T info) { this.info = info; link = null; } public void setInfo(T info) { this.info = info; } public T getInfo() { return info; } public void setLink(CharNode link) { this.link = link; } public CharNode getLInk(){ return link; } // 10 End of your code }

Task 1 Design and implement a simple stack for char. Two .java files are provided which are CharNode.java and CharStack.java. You are required to complete the classes with your design and implementation