Submit Chapter5.java with \" public static\" methods for solutions of these Exer
ID: 3760508 • Letter: S
Question
Submit Chapter5.java with "public static" methods for solutions of these Exercises starting on page 381:
A. Exercise #18: digitSum, do not use String
write a method called digitSum that accepts an integer as a parameter and returns the sum of the digits of that number.
B. Exercise #20: digitRange, do not use String
write a mthod called digitRange that accepts a integer as a parameter and returns the range of values of its digits.
C. Write a method randColor() that returns a String which will randomly be one of the three primary colors ("red" or "yellow" or "blue").
D. Write a boolean method isValidHex that determines if a single String parameter contains only hexadecimal digits (0-9, a-f, A-F). For example, returns true, isValidHex("A932B") returns true, and isValidHex("anythingElse") returns false. Your method cannot throw exceptions and must use an if-else block.
Explanation / Answer
import java.util.Random;
public class Chapter5 {
public static int digitSum(int n) {
int sum=0;
while (n!=0) {
sum+=n%10;
n=n/10;
}
return sum;
}
public static int[] digitRange(int n) {
int min=n%10;
int max=n%10;
n=n/10;
while (n!=0) {
int temp = n%10;
if (temp < min) {
min = temp;
}
if (temp > max) {
max = temp;
}
n=n/10;
}
int[] range = new int[2];
range[0] = min;
range[1] = max;
return range;
}
public static String randColor() {
Random r = new Random();
int c = r.nextInt(3);
return (c == 0 ? "Red" : (c == 1 ? "Yellow" : "Blue"));
}
public static boolean isValidHex(String hex) {
for (int i = 0; i < hex.length(); i++) {
if (!((hex.charAt(i) >= 'a' && hex.charAt(i) <= 'f') ||
(hex.charAt(i) >= 'A' && hex.charAt(i) <= 'F') ||
(hex.charAt(i) >= '0' && hex.charAt(i) <= '9'))) {
return false;
}
}
return true;
}
public static void main(String[] args) {
System.out.println(digitSum(1234));
}
}