Java：检查一个数字是两位数还是一位数没有if语句？
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Java: Check if a number is a double digit or single-digit no if statement?
提问by user3819756
I have homework to check if number is a double digit or a single-digit without using if statement. Thanks for your help!
我有作业要在不使用 if 语句的情况下检查数字是两位数还是一位数。谢谢你的帮助！
public class SchoolTest {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
int x;
System.out.println("Please enter a number");
x = reader.nextInt();
if ((x > 9 && x < 100) || (x < -9 && x > -100)) {
System.out.println(true);
main(args);
} else {
System.out.println(false);
main(args);
}
}
}
回答by Gavin
You could read the number in as a String rather than an int and use Regex
您可以将数字作为 String 而不是 int 读入并使用 Regex
回答by clcto
Just set the value to the conditional:
只需将值设置为条件：
boolean isDoubleDigit = (x > 9 && x < 100) || (x < -9 && x > -100);
System.out.println( isDoubleDigit );
回答by spb1994
public class Digits {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int check = scan.nextInt();
//False for single digit, true for double digit
boolean isDoubleDigit = (check / 10 == 0 && check / 100 == 0) ? false : true;
System.out.println(isDoubleDigit);
}
}
Ternary operator is quite helpful in your case
三元运算符对您的情况非常有帮助
回答by Hot Licks
If the number is known to be non-negative:
如果已知数字为非负数：
int digits = Integer.toString(theIntValue).trim().length();
(trim()probably isn't needed.)
（trim()可能不需要。）
If it might be negative:
如果它可能是负数：
int digits = Integer.toString(Math.abs(theIntValue)).trim().length();
If you must return a boolean:
如果你必须返回一个布尔值：
boolean isTwoDigit = Integer.toString(Math.abs(theIntValue)).trim().length() == 2;
回答by Shane parker
Should have been written without the main (args)
应该在没有主要（参数）的情况下编写
