Question 1. Write static methods as follows:
• double sum(double[] a) - returns the sum of the entries in the array a.
• double[] fill(int n, double v) - returns an array of n doubles, all of whose values are v.
• double[] random (int n) - return an array of n random doubles.
• double min(double[] a) - returns the minimum element of the array a.
• double max(double[] a) - returns the maximum element of the array a.
• double average(double[] a) - returns the average (or mean) of the elements of the array a.
• double variance(double[] a) - returns the variance of the elements of the array a (note: this method should call your average method).
• double stdDev(double[] a) - returns the standard deviation of the elements of the array a (note: this method should call your variance method).
• double[] read() - reads an array from the keyboard and returns it (read the number of elements first, and then that many numbers).
• void print(double[] a) - prints an array, a, on a single line with commas between elements (do NOT use Arrays.toString()).
Write a Main class with a main method that tests your methods appropriately (i.e. by calling each method at least once with various inputs), and printing the results.
Question 2. Consider the following method and method call:
public static int inc(int a) {
a++;
return a;
}
int a = 10;
int b = inc(a + 12);
int c = inc(a);
System.out.println(a);
System.out.println(b);
System.out.println(c);
What is the output from this code? Carefully explain your answer (i.e. carefully show how the method
inc is called).
Question 3. Consider the following method and method call:
public static int[] inc(int[] a) {
a[0]++;
return a;
}
int[] a = { 10, 20, 30, 40 };
int[] b = inc(a);
System.out.println(b[0]);
System.out.println(a[0]);
What is the output from this code? Carefully explain your answer (i.e. carefully show how the method
inc is called).
Question 4. Consider the following code:
int[] a = { 10, 20, 30, 40 };
int[] b = a;
int[] c = { 10, 20, 30, 40 };
System.out.println(a == b);
System.out.println(a == c);
What is the output from this code? Carefully explain your answer.