Problems with Scanner input - input

Question

I am new to JAVA. I don't understand why JAVA give me two souts.
(Input row & column (throw 1 space): Input row & column (throw 1 space): )
In the first pass, it does not wait for my input and think str = "". And in the second pass its waiting for my input.
Ssory, I forgot to tell that beforе this block of code - my Scanner was opened. I asked program:
while (true) {
System.out.print("Enter game size (3 - 20): ");
if (SCAN.hasNextInt()) {
return SCAN.nextInt();
}
System.out.println(SCAN.next() + " - not a number!");
I think I should clear scanners buffer ( /n ). But I dont know how.
private static void humanTurn() {
System.out.println("HUMAN TURN");
String str;
String regex = "\\d{1,2}\\s\\d{1,2}";
Pattern myPattern = Pattern.compile(regex); // Pattern for checking
boolean checkPattern;
int x, y;
do {
do {
System.out.print("Input row & column (throw 1 space): ");
str = SCAN.nextLine();
Matcher myMatcher = myPattern.matcher(str);
checkPattern = myMatcher.matches();
} while (!checkPattern);
String[] strArr = str.split(" ");
x = Integer.parseInt(strArr[0]) - 1;
y = Integer.parseInt(strArr[1]) - 1;
} while (!isValidCell(x, y));

Answer 1

I have tried to guess your code. This is what I come up with. Still works fine. Let me know if anything else.
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
private static Scanner sc = new Scanner(System.in);
private static int size = 0;
public static void main(String[] args) {
size = getBoardSize();
humanTurn();
}
private static int getBoardSize() {
while (true) {
System.out.print("Enter game size (3 - 20): ");
if (sc.hasNextInt()) {
return sc.nextInt();
}
System.out.println(sc.next() + " - not a number!");
}
}
private static void humanTurn() {
System.out.println("HUMAN TURN");
String str;
String regex = "\\d{1,2}\\s\\d{1,2}";
Pattern myPattern = Pattern.compile(regex); // Pattern for checking
boolean checkPattern;
int x, y;
do {
do {
System.out.print("Input row & column (throw 1 space): ");
str = sc.nextLine();
Matcher myMatcher = myPattern.matcher(str);
checkPattern = myMatcher.matches();
} while (!checkPattern);
String[] strArr = str.split(" ");
x = Integer.parseInt(strArr[0]) - 1;
y = Integer.parseInt(strArr[1]) - 1;
} while (!isValidCell(x, y));
}
private static boolean isValidCell(int x, int y) {
return x < size && y < size && x >= 0 && y >= 0;
}
}