Java Review

Given the following program:

Answer the following questions:

Q 1:	What does this program do when executed from the following command line: java echo

Q 2:	What does this program do when executed from the following command line: java echo This old man, he played one

Q 3:	What does this program do when executed from the following command line: java echo "This old man, he played one"

Given the following program:

Source code: runTests.java

public class V2 { public static int[] vowelCount(String s) { int[] ret = new int[5]; int i=0; String temp=""; temp = s.toUpperCase(); for(i=0; i<5; i++) ret[i] = 0; // no vowels found for (i = 0; i < s.length(); i++) switch (temp.charAt(i)) { case 'A': ret[0]++; break; case 'E': ret[1]++; break; case 'I': ret[2]++; break; case 'O': ret[3]++; break; case 'U': ret[4]++; break; default: } return ret; } public static void main(String[] args) { int i = 0; int[] vc = new int[5]; vc = vowelCount("This old man, he played one."); for (i=0; i<5; i++) System.out.println("vowel count[" + i + "] = " + vc[i]); } }

Answer the folling questions:

Q 4:	What is the output from this program when executed from the following command line: java V2

Q 5:	What does the third line of output represent?

Q 6:	What is the purpose of the folling line from the vowelCount method? temp = s.toUpperCase() Where is toUpperCase() defined?

Given the following program that uses a recursive method guessMyFunction called from the main progam:

Source code: runTests.java

import java.util.Scanner; public class runTests { public static int guessMyFunction (int n) { if (n < 0) return -guessMyFunction (-n); else if (n < 10) return (n + 1) % 10; else return 10 * guessMyFunction (n / 10) + (n + 1) % 10; } public static void main(String[] args) { int[] testData = {7, 42, -790, 89294}; int val = 0; for (int i=0; i<testData.length; i++) { val = guessMyFunction(testData[i]); System.out.println("guessMyFunction(" + testData[i] + ") = " + val); } } // main } // runTests

Answer the folling questions:

Q 4:

When the program is executed from the following command line: java runTests the main progam will loop through the array named testData, and call guessMyFunction with each element. Trace the values of guessMyFunction when called with a 0, 1, 2, 3, 4 and -1 and then identify what the program output when the main program is executed.