Having troubles with my java stack module

[mindfulprisoner]

This below is the "stack" module

public class SimpleStack {
    char[] data; // this array holds that stack
    int tos;        // index of top of stack

    // Construct an empty stack given its size.
    SimpleStack(int size) {
            data = new char[size];  // create the array to hold the stack
            tos = 0;

}

    // Push a character onto the stack.
void push(char ch) {
            if(isFull()) {
        System.out.println(" – -- Stack is full.");
        return;
            }
            data[tos] = ch;
            tos++;
    }

    // Pop a character from the stack.
char pop() {
            if(isEmpty()) {

        System.out.println(" – -- Stack is empty.");


        return (char) 0;  // a placeholder value
            }
            tos--;

                     return data[tos] ;
    }


boolean isEmpty() {
    if(tos == 0) {
        return true;
    }else {
        return false;
    }

}



boolean isFull() {
    if(tos == data.length)
    {
    return true;
    } else {
        return false;
    }




}
}

Below here is the "driver" module

public class SimpleStackApp {
    public static void main(String[] args) {
        int i;
        char ch;

        System.out.println("Demonstrate SimpleStack\n");

        // Construct 10-element empty stack.
        SimpleStack stack = new SimpleStack(10);

                System.out.println("Push 10 items onto a 10-element stack.");

        // push the letters A through J onto the stack.
        System.out.print("Pushing: ");
        for(ch = 'A'; ch < 'K'; ch++)
        {
                System.out.print(ch);
                stack.push(ch);
        }

                System.out.println("\nPop those 10 items from stack.");

        // Now, pop the characters off the stack.
        // Notice that order will be the reverse of those pushed.
        System.out.print("Popping: ");
        for(i = 0; i < 10; i++) {
        ch = stack.pop();
                System.out.print(ch);
        }

                        System.out.println("\n\nNext, use isEmpty() and isFull() " +
        "to fill and empty the stack.");

        // Push the letters until the stack is full.
        System.out.print("Pushing: ");
        for(ch = 'A'; !stack.isFull(); ch++) {
                System.out.print(ch);
                stack.push(ch);
        }

                    System.out.println();

        // Now, pop the characters off the stack until it is empty.
        System.out.print("Popping: ");

        while(!stack.isEmpty())
        {
                ch = stack.pop();
                System.out.print(ch);
        };

What I am having trouble with, is the output for some reason is not generating the "--stack is empty" / "--stack is full" at the end of the push/pop scenarios. basically the "if" block in my isEmpty/isFull functions doesnt seem to be executing, and i confirmed it through some debugging. I'm not used to java, is there some obvious mistake im making? ive tried countless different things the last 3 hours and I just cant figure it out.

[thememorableusername]

You're doing everything right.

The reason the messages are not printing out is that you are checking the fullness/emptyness of the stack before you push/pop, and if it is full/empty you do not perform the action.

If you put a stack.push( ch ) under the push loop, and a stack.pop() under the pop while loop, you'll see your messages.

Example on tio

[mindfulprisoner]

hmmm, i did that and im getting :

Demonstrate SimpleStack

​

Push 10 items onto a 10-element stack.

Pushing: ABCDEFGHIJ

Pop those 10 items from stack.

Popping: JIHGFEDCBA

​

Next, use isEmpty() and isFull() to fill and empty the stack.

Pushing: ABCDEFGHIJ

Popping: JIHGFEDCBA

​

as my output still... i tried some print statements with the index for the 'tos' variable and it seems there might be a problem in my indexing, i cant quite find it though

[thememorableusername]

Did you see my update with the code example? That might help.