Java Scanner doesn't wait for user input

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Scanner is skipping nextLine() after using next() or nextFoo()? 15 answers

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It's possible that you are calling a method like nextInt() before. Thus a program like this:

Scanner scanner = new Scanner(System.in);
int pos = scanner.nextInt();
System.out.print("X: ");
String x = scanner.nextLine();
System.out.print("Y: ");
String y = scanner.nextLine();

demonstatres the behavior you're seeing.

The problem is that nextInt() does not consume the 'n' , so the next call to nextLine() consumes it and then it's waiting to read the input for y .

You need to consume the 'n' before calling nextLine() .

System.out.print("X: ");
scanner.nextLine(); //throw away the n not consumed by nextInt()
x = scanner.nextLine();
System.out.print("Y: ");
y = scanner.nextLine();

(actually a better way would be to call directly nextLine() after nextInt() ).

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只要为你的代码尝试这个构造构造：

    System.out.print("X: ");
    scanner.nextLine();
    x = scanner.nextLine();
    System.out.print("Y: ");
    scanner.nextLine();
    y = scanner.nextLine();

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