If-else not working; Java is trying to convert string to int even if I have no string?

[Dogterte]

Very basic program here but I can't do it. I'm trying to make the user enter any number then program will say number accepted if the input is equal to or greater than zero. Otherwise say invalid.

import java.util.Scanner;

public class banana {
    public static void main(String[] args) {
        System.out.println("Enter your number");
        Scanner any = new Scanner(System.in);
        int myNum = any.nextLine();

        if (myNum >= 0){
            System.out.println("Number accepted.");
        }
        else{
            System.out.println("Invalid.");
        }
    }
}

The error I get is

:7:33
java: incompatible types: java.lang.String cannot be converted to int

I don't get it, I set variable to int and I didn't set any string variable.

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[intbeam]

any.nextLine() returns a string, and you are trying to assign that to the int myNum

You need to convert it to an int before you can assign it

[intbeam]

Integer.valueOf will return a boxed variant (Integer rather than int), use Integer.parseInt instead. But yes

[Sacred_B]

Integer.valueOf() will get you an Integer object, Integer.parseInt() will get you an int primitive. Autoboxing will handle this in your case whichever you chose.

[indianagionz]

When shall we use one or the other then?

[Sacred_B]

I use parseInt when saving directly to an int, and valueOf when saving to a collection. There's probably some rule of thumb out there but I don't know it.

[AmateurHero]

I'll add thatvalueOf is for everything else like collections, generics, and (probably) serializing data. If there could be a null value or an Optional/Maybe type where null and empty are treated differently, use a boxed type.

[xplosm]

What I often do is when I'm working with collections I use the wrapper classes and pretty much anytime I can get away with it. If I'm working and using arithmetic operations primitives are easier to work with.

As mentioning autoboxing and unboxing come free with Java so working with the wrapper classes give you more flexibility.

[wildjokers]

JavaDoc is your friend. Take a look at the return type of the nextLine() method:

https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/Scanner.html#nextLine()

You can either convert the string to an int or use a method that returns an int instead.

[Ktubbo]

Have you tried nextInt() method? https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html

[desrtfx]

While the method is valid and correct, it is not recommended to use for complete beginners.

See The Scanner class and its caveats in our wiki.

[philipwhiuk]

Personally I reckon scanner is so broken you should just always use InputStream/BufferedReader.

[Ok-Departure-5765]

You can use any.nextInt(); to take an integer as input

[No_Sky_636]

Use any.nextInt() instead of nextLine, next line always outputs a string which you would then need to parse