JAVA语言程序设计（第8版）第5章完整答案programming exercises（程序练习题）答案完整版

}

public static String convertMillis(long millis) { //Obtain the total seconds long totalSeconds = millis / 1000; //Compute the remaining seconds long remainingSeconds = totalSeconds % 60; //Obtain the total minutes long totalMinutes = totalSeconds / 60; //Compute the remaining minutes long remainingMinutes = totalMinutes % 60; //Obtain the total hours long totalHours = totalMinutes / 60; return totalHours + \}

5.26

public class Exercise26 { public static void main(String[] args) { int countOfPalindromicPrimes = 0; int count = 1; int i = 2; while (countOfPalindromicPrimes < 100) { if (isPrime(i) && isPalindrome(i)) { if (count % 10 != 0) System.out.printf(\ else System.out.printf(\ count++; countOfPalindromicPrimes++; } i++; } } public static boolean isPrime(int m) { boolean isPrime = true;

}

for (int j = 2; j <= m / 2; j++) { if (m % j == 0) { isPrime = false; break; } } return isPrime; }

public static boolean isPalindrome(int n) { if (n == reverse(n)) return true; else return false; }

public static int reverse(int n) { int reverseNumber = 0; do { int digit = n % 10; n = n / 10; reverseNumber = reverseNumber * 10 + digit; } while (n != 0); return reverseNumber; }

5.27

public class Exercise27 { public static void main(String[] args) { int countOfEmirps = 0; int countOfEmirpsPerLine = 1; int i = 2; while (countOfEmirps < 100) { if (isPrime(i) && isNonpalindrome(i) && isPrime(reverse(i))) { if (countOfEmirpsPerLine % 10 != 0) System.out.printf(\ else System.out.printf(\

}

countOfEmirps++; countOfEmirpsPerLine++; } i++; } }

public static boolean isPrime(int n) { boolean isPrime = true; for (int i = 2; i <= n /2; i++) { if (n % i == 0) { isPrime = false; break; } } return isPrime; }

public static boolean isNonpalindrome(int n) { if (n == reverse(n)) return false; else return true; }

public static int reverse(int n) { int reversal = 0; do { int digit = n % 10; n = n / 10; reversal = reversal * 10 + digit; } while (n != 0); return reversal; }

5.28

public class Exercise28 { public static void main(String[] args) {

}

System.out.println(\ for (int p = 2; p <= 31; p++) { if (isPrime(Math.pow(2, p) - 1)) System.out.println(p + \ } }

public static boolean isPrime(double n) { boolean isPrime = true; for (int i = 2; i <= n /2; i++) { if (n % i == 0) { isPrime = false; break; } } return isPrime; }

5.29

public class Exercise29 { public static void main(String[] args) { //Generate two random numbers between 1 and 6 int i = (int)(Math.random() * 6 + 1); int j = (int)(Math.random() * 6 + 1); if (isCraps(i, j)) System.out.println(\ if (isNatural(i, j)) System.out.println(\ if (isPoint(i, j)) point(i, j); } public static int sum(int n, int m) { return n + m; } public static boolean isCraps(int i, int j) { boolean isCraps = false;