EXAMPLES

1. EXAMPLES

2. Example 1: • Write a Java method that performs addition on two binary numbers. Each binary number is kept in an integer array. 11 1010 0101 + 1 0111 0001 --------------- 101 0001 0110

3. private static int [] binaryAddition(int[] A, int []B){ int[] C = newint [max(A.length,B.length) + 1]; int curA = A.length - 1; int curB = B.length - 1; int carry = 0; for (int i = C.length - 1; i >= 0; i--){ int sum = 0; if (curA >= 0){ sum += A[curA]; curA--; } if (curB >= 0){ sum += B[curB]; curB--; } C[i] = (carry + sum) % 2; carry = (carry + sum) / 2; } return C; }

4. private static int max(int A, int B){ if (A > B) return A; else return B; }

5. Example 2: • Write a Java method that combines two sorted integer arrays into a third sorted integer array

6. private static int [] combineArrays(int[] A, int[] B){ int[] C = newint[A.length + B.length]; int curA, curB, curC; curA = curB = curC = 0; while (curA < A.length && curB < B.length){ if (A[curA] < B[curB]) C[curC++] = A[curA++]; else C[curC++] = B[curB++]; } if (curA < A.length) while (curA < A.length) C[curC++] = A[curA++]; else while (curB < B.length) C[curC++] = B[curB++]; return C; }

7. Example 3: • Write a program that takes the first and last names from the user and outputs two fancy greetings for this name. • For example, if the input is "Cigdem" and "Gunduz-Demir", then the greetings should look like **************** * Hello! * * Cigdem * * Gunduz-Demir * **************** **************************** * H o g G u e * * e l ! i d m u d z D m r * * l C e n - i * **************************** • The latter should be formed by concatenating the strings "Hello!", "Cigdem", and "Gunduz-Demir" and outputting it in a wave pattern

8. import java.util.*; public class Greetings{ public static void main(String[] args){ Scanner scan = new Scanner(System.in); System.out.print("Enter your first name: "); String firstName = scan.next(); System.out.print("Enter your last name: "); String lastName = scan.next(); displayGreeting("Hello!",firstName,lastName); System.out.println(); displayGreetingInWaveForm("Hello!",firstName,lastName); }

9. private static void displayGreeting(String s1, String s2, String s3){ int lineLen = maxLengthOfThree(s1,s2,s3) + 4; writeHeader(lineLen); writeStringOnSingleLine(s1,lineLen); writeStringOnSingleLine(s2,lineLen); writeStringOnSingleLine(s3,lineLen); writeHeader(lineLen); }

10. private static int maxLengthOfThree(String s1, String s2, String s3){ int maxLen = s1.length(); if (maxLen < s2.length()) maxLen = s2.length(); if (maxLen < s3.length()) maxLen = s3.length(); return maxLen; }

11. private static void writeHeader(int lineLen){ for (int i = 0; i < lineLen; i++) System.out.print("*"); System.out.println(); }

12. private static void writeStringOnSingleLine(String S, int lineLen){ int spaceNo = lineLen - 4 - S.length(); int leftSpaceNo = spaceNo / 2; int rightSpaceNo = spaceNo - leftSpaceNo; System.out.print("* "); for (int i = 0; i < leftSpaceNo; i++) System.out.print(" "); System.out.print(S); for (int i = 0; i < rightSpaceNo; i++) System.out.print(" "); System.out.println(" *"); }

13. private static void displayGreetingInWaveForm(String s1, String s2, String s3){ String all = s1 + s2 + s3; char [][] lines = newchar[3][all.length()]; for (int i = 0; i < lines.length; i++) for (int j = 0; j < lines[0].length; j++) lines[i][j] = ' '; for (int i = 0; i < all.length(); i += 4) lines[0][i] = all.charAt(i); for (int i = 1; i < all.length(); i += 2) lines[1][i] = all.charAt(i); for (int i = 2; i < all.length(); i += 4) lines[2][i] = all.charAt(i); writeHeader(all.length() + 4); for (int i = 0; i < lines.length; i++){ System.out.print("* "); for (int j = 0; j < lines[0].length; j++) System.out.print(lines[i][j]); System.out.println(" *"); } writeHeader(all.length() + 4); } }

14. Example 4: • Write a card shuffling and dealing simulation program. This program shuffles a deck of 52 playing cards and then deal these cards to 4 players. • Suits: Hearts, Diamonds, Clubs, Spades • Faces: 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A

15. import java.util.*; public class CardDealing { public static void main(String[] args){ String[] faces = {"2","3","4","5","6","7","8", "9","10","J","Q","K","A"}; String[] suits = {"Hearts","Diamonds", "Clubs","Spades"}; String[] deck = newString[52]; String[][] hands; for (int i = 0; i < deck.length; i++) deck[i] = faces[i % 13] + " " + suits[i / 13]; printDeck(deck); // sorted deck shuffle(deck); printDeck(deck); // shuffled deck hands = deal(deck,4); printHands(hands); } // write your helper methods here }

16. private static void printDeck(String[] deck){ for (int i = 0; i < deck.length; i++) System.out.println(deck[i]); }

17. private static void shuffle(String[] deck){ Random rand = newRandom(); for (int i = 0; i < deck.length; i++){ int rno = rand.nextInt( 52 ); String temp = deck[i]; deck[i] = deck[rno]; deck[rno] = temp; } }

18. private staticString [][] deal(String[] deck, int playerNo){ String[][] hands = newString [playerNo][deck.length / playerNo]; int cnt = 0; for (int i = 0; i < hands[0].length; i++){ for (int j = 0; j < hands.length; j++){ hands[j][i] = deck[cnt]; cnt++; } } return hands; }

19. privatestaticvoid printHands(String[][] hands){ for (int i = 0; i < hands.length; i++){ System.out.print("Player" + i + "\t\t"); } System.out.println(); for (int i = 0; i < hands[0].length; i++){ for (int j = 0; j < hands.length; j++){ System.out.print(hands[j][i] + " \t"); } System.out.println(); } }