我正在尝试使用扫描仪对象sc从用户的输入中读取整数,并需要评估它是否大于0。所以我在 while() 中设置了以下 OR 条件来检查它是空行还是输入数字小于 0。但程序在遇到无效输入后不会接受输入。任何帮助,不胜感激。
Scanner sc = new Scanner(System.in);
while (!sc.hasNextInt() || sc.nextInt() <= 0)
{
System.out.println("Invalid inputn the number needs to be greater than 0");
sc.next();
}
int number = sc.nextInt();
问题可能是您在该条件下消耗了 nextInt。 您应该将其读入变量:
包装测试;
import java.util.Scanner;
public class ScannerTest {
public static void main(String[] arg) {
Scanner sc = new Scanner(System.in);
int input=-1;
while(input<0){
while (!sc.hasNextInt()) {
if(sc.hasNext()){
String s = sc.next(); /* read things that are not Integers */
System.out.println("Invalid input:" + s);
}
}
input = sc.nextInt();
if(input<0){
System.out.println("Please input a positive integer.");
}
}
System.out.println("Valid input was "+input);
}
}