Must type multiple times, before scanner reads input

If I run this code

Scanner sc = new Scanner();
while (true) {
        if (sc.next().equals("1"))
            System.out.println("--1--");

        else if (sc.next().equals("2"))
            System.out.println("--2--");

        else if (sc.next().equals("3"))
            System.out.println("--3--");

        else if (sc.next().equals("4"))
            System.out.println("--4--");

        else if (sc.next().equals("help"))
            System.out.println("--help--");
    }

It will not read the first time I type enter. I have to type 2-4 times before it reads the input. A session could look like this:

1
1
1
1
--1--
3
3
--3--
help
2
1
help
--help--

No matter what I type, it will only read the last input of the four inputs. Sometimes it reads after two inputs. I'm really confused about this. Should I instead use multiple scanners?

Jon Skeet
people
quotationmark

You're calling sc.next() multiple times - so if the input isn't 1, it's going to wait for more input to see whether the next input is 2, etc. Each call to sc.next() will wait for more input. It doesn't have any idea of "that isn't the input you were looking for, so I'll return the same value next time you call".

Use a local variable to store the result of sc.next()

while (true) {
    String next = sc.next();
    if (next.equals("1"))
        System.out.println("--1--");
    else if (next.equals("2"))
        System.out.println("--2--");
    else if (next.equals("3"))
        System.out.println("--3--");
    else if (next.equals("4"))
        System.out.println("--4--");
    else if (next.equals("help"))
        System.out.println("--help--");
}

Also consider using a switch statement instead...

people

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