Java Scanner doesn't wait for user input
This question already has an answer here:
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()
).
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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