Programming 2 LAB

1. Programming 2 LAB TA: Nouf Al-Harbi NoufNaief.net ::: nouf200@hotmail.com

2. Lab 2 The StringClass Applications

3. Program Phone keypads

4. Problem Description: • The international standard letter/number mapping found on the telephone is shown below: Phone keypads

5. Write a method that returns a number, given an uppercase letter, as follows: public static intgetNumber(char uppercaseLetter) • Write a test program that prompts the user to enter a phone number as a string. The input number may contain letters. The program translates a letter (upper- or lowercase) to a digit and leaves all other characters intact. Phone keypads

6. <Output> • Enter a string: 1-800-Flowers • 1-800-3569377 • <End Output> • <Output> • Enter a string: 1800flowers • 18003569377 • <End Output> Phone keypads

7. Solution..

8. importjava.util.Scanner; publicclass Exercise9_7 { publicstaticvoid main(String[] args) { Scanner input = newScanner(System.in); // Prompt the user to enter a string System.out.print("Enter a string: "); String s = input.nextLine(); for (int i = 0; i < s.length(); i++) { if (Character.isLetter(s.charAt(i))) System.out.print(getNumber(Character.toUpperCase(s.charAt(i)))); else System.out.print(s.charAt(i)); } }

9. case'M': case'N': case'O': number = 6; break; case'P': case'Q': case'R': case'S': number = 7; break; case'T': case'U': case'V': number = 8; break; case'W': case'X': case'Y': case'Z': number = 9; break; } return number; } } publicstaticintgetNumber(charuppercaseLetter) { int number = 0; switch (uppercaseLetter) { case'A': case'B': case'C': number = 2; break; case'D': case'E': case'F': number = 3; break; case'G': case'H': case'I': number = 4; break; case'J': case'K': case'L': number = 5; break;

10. Program Checking Password

11. Problem Description : • Some Websites impose certain rules for passwords. Write a method that checks whether a string is a valid password. Suppose the password rule is as follows: • A password must have at least eight characters. • A password consists of only letters and digits. • A password must contain at least two digits. • Write a program that prompts the user to enter a password and displays "valid password" if the rule is followed or "invalid password" otherwise. Checking Password

12. Sample 1 • Enter a string for password: wewew43x • valid password • Sample 2 • Enter a string for password: 343a • invalid password Checking Password

13. Solution..

14. publicclass Test { publicstaticvoid main(String[] args) { // Prompt the user to enter a password java.util.Scanner input = newjava.util.Scanner(System.in); System.out.print("Enter a string for password: "); String s = input.nextLine(); if (isValidPassword(s)) { System.out.println("Valid password"); } else { System.out.println("Invalid password"); } }

15. /** Check if a string is a valid password */ publicstaticbooleanisValidPassword(String s) { // Only letters and digits? for (int i = 0; i < s.length(); i++) { if (!Character.isLetter(s.charAt(i)) && !Character.isDigit(s.charAt(i))) returnfalse; } // Check length if (s.length() < 8) returnfalse; // Count the number of digits int count = 0; for (int i = 0; i < s.length(); i++) { if (Character.isDigit(s.charAt(i))) count++; } if (count >= 2) returntrue; else returnfalse; } }

16. End of Lab 2