Description
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.
