Scanner scanner = new Scanner(System.in);
System.out.println("0以上の整数を入力してください > ");
int num = 0;
try {
num = Integer.parseInt(scanner.nextLine());
} catch (NumberFormatException e) {
System.err.println("数字を入力してください");
scanner.close();
return;
}
if (num <= 0) {
System.err.println("0以上の整数を入力してください");
scanner.close();
return;
}
int i = 2;
String result = num + " = ";
while (num != 1) {
if (num % i == 0) {
result += i + " * ";
num /= i;
} else {
i++;
}
}
System.out.println(result.substring(0, result.length() - 3));
scanner.close();