HasNextInt() Infinite loop [closed]

问题

//input: multiple integers with spaces inbetween
    Scanner sc = new Scanner(System.in);
    while(sc.hasNextInt())
    {
      //add number to list
    }

sc.hasNextInt() is waiting for an integer. It only breaks out if you input a non-integer character.

I saw a solution here before not too long ago but i cant find it anymore.

The solution (was the best if you ask me) was using two scanners. I cant seem to figure out how it used two scanners to go around this problem.

sc.NextLine() maybe?

A user can input multiple integers the amount is unknown. Ex: 3 4 5 1. There is a space inbetween them. All i want to do is read the integers and put it in a list while using two scanners.

回答1:

Based on your comment

A user can input multiple integers the amount is unknown. Ex: 3 4 5 1. There is a space inbetween them. All i want to do is read the integers and put it in a list while using two scanners.

You are probably looking for:

scanner which will read line from user (and can wait for next line if needed)
another scanner which will handle splitting each number from line.

So your code can look something like:

List<Integer> list = new ArrayList<>();
Scanner sc = new Scanner(System.in);
System.out.print("give me some numbers: ");
String numbersInLine = sc.nextLine();//I assume that line is in form: 1 23 45 

Scanner scLine = new Scanner(numbersInLine);//separate scanner for handling line
while(scLine.hasNextInt()){
    list.add(scLine.nextInt());
}
System.out.println(list);

回答2:

Try this:

while (sc.hasNext()) {
    if (sc.hasNextInt()) {
       // System.out.println("(int) " + sc.nextInt());
       // or add it to a list
    }
     else {
       // System.out.println(sc.next());
       // or do something
    }
}

回答3:

    Scanner sc = new Scanner(System.in);
    while(sc.hasNextInt())
    {

        System.out.println("Hi");
        System.out.println("Do you want to exit ?");
        Scanner sc2 = new Scanner(System.in);
        if(sc2.next().equalsIgnoreCase("Yes")){
            break;
        }
     }

来源：https://stackoverflow.com/questions/33084212/hasnextint-infinite-loop

标签

java

loops

infinite