Assignment 4, due Feb 12

class X {
        private int i = 1;
        public int j = 2 * i;
        private X(){}
        public X( int i ){
                this.i = i;
        }
        ... other methods of X ...
}
... other classes that use instances of X ...

a) Where is it legal to write X x = new X(); (0.4 points)

b) Suppose the program worked correctly, and then someone deleted the line private X(){}. Would the program still work correctly? (0.3 points)

c) After the call to X x = new X(5); what is the value of x.j?

    public class Neuron {
            String name;     // the name of this neuron.
            float threshold; // the threshold voltage for this neuron.
            float voltage;   // the voltage of this neuron at the given time.
            float time;
            LinkedList <Synapse> synapses;
    }

The simulation starts at time 0.0, that is the initial value of time. The list synapses starts out empty. The other fields are initialized from a neural network description file. The lines of this file dealing with neurons look like this:

    neuron A 1.0 0.95
    neuron B 1.0 0.0

The first number after the neuron name is the threshold, the second number is the voltage at time 0.0

a) Write an initializer for class Neuron that takes a Scanner as a parameter and scans one line of the input file, scanning the name and the initial values from the input file. Note that the caller of this initializer should have already scanned over the keyword neuron since the caller would only initialize a new neuron when a line of the input file begins with that keyword.

For this assignment, do not worry about detecting duplicate names. Turn in legible well formatted and commented code. You need not test this code, but you will be graded on correctness and readability. (1.0 points)

// initializer
public Neuron( Scanner sc ) {
        // scan and process one neuron
        name = sc.next();           // the neuron name
        threshold = sc.nextFloat(); // the neuron threshold
        // Bug: what if no next float?
        voltage = sc.nextFloat();   // the initial voltage of this neuron
        // Bug: what if no next float?
        time = 0.0;                 // the initial time
        // synapses is already null
        String skip = sc.nextLine();
        // Bug:  What if more junk at end of line (skip not empty)
}

b) Write a ToString() method for objects of class Neuron that returns a string representing the entire line of the input file that could have been used to initialize that object.

Turn in legible well formatted and commented code. You need not test this code, but you will be graded on correctness and readability. (1.0 points)

// other methods
public String toString() {
        return (
                "Neuron " +
                name + " " +
                threshold + " " +
                voltage
        );
}