Java错误：线程“ main”中的异常java.lang.RuntimeException

Question

I am running a Program in CMD.

I am using 2 methods to have it print out like the below:

Print all characters between a and w:
abcdefghij
klmnopqst
uvw

Below is what I have so far ... But I can not get past here. I keep getting all sorts of errors.

public class Letters{
public static void main (String[] args) {
System.out.println("Print all characters between a and w");

for (char i = 0; i <= 10; i++) {
String myrow = printChars('a','w');
System.out.println(myrow);
}
}
public static void printChars (char c1, char c2){


}
}

Answer 1

First of, I recommend to properly indent your code, making it easier to read. Second as you are using char you can just check against the value of the character. char c = 'a' like that. If you increment c it then has the value of b .

public class Letters
{
    public static void main (String[] args) {
        System.out.println("Print all characters between a and w");

        for (char c = 'a'; c <= 'w'; c++) {
            System.out.print(c);
            if ((c+1 - 'a') % 10 == 0) {
                System.out.println();
            }
        }

        System.out.println("\n");

        printChars ('d','z');
    }

    public static void printChars (char c1, char c2) {
        // no valid range, can also add checks to see if they are actual letters
        if (c1 > c2) {
            return;
        }

        System.out.println("Print all characters between " + c1 + " and " + c2);
        for (char c = c1; c <= c2; c++) {
            System.out.print(c);
            if ((c+1 - c1) % 10 == 0) {
                System.out.println();
            }
        }
    }
}

This part checks what iteration is currently being done, it then checks if that iteration is divisible by 10, to add a new line, if not, move along.

if ((c+1 - 'a') % 10 == 0) {
    System.out.println();
}

Answer 2

public static void main( String[] args )
{
    char c1='a';
    char c2='w';

    String str= "a b c d e f g h i j k l m n o p q s t u v w";
    Pattern compile = Pattern.compile(".*"+c1+"(.*)"+c2+".*");
    Matcher matcher = compile.matcher(str);
    boolean found = matcher.find();
    System.out.println("found:"+ found);
    if (found) System.out.println(matcher.group(1));

}

Answer 3

E:\\Java>jdk1.8.0_111\\bin>java -jar selenium-server-standalone-3.0.0.jar -htmlsuite " *firefox "C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe" " https://www.google.com/ " "E:\\Selenium\\newsuite.html" "E:\\Selenium\\result.html"

i got the above mentioned error.please help