CODEWITHSUNDEEP
javasorting
Nele
Nele

Reputation: 97

operator < is undefined for the argument type(s) Integer, int error

I'm trying to write a code to get given number of repeated times of a input string.

Not written too much code, but here is my code:

public class MultipleCopiesString {
    public static void StringCopy(String inp, Integer num) {
        for (int i = 0; i < num; i++){
        }
    }
}

I'm getting error in for loop (i < num), I want to know why its coming and how it can be resolved.

Java version is 1.8 and creating code on eclipse.

Upvotes: 0

Views: 13079

Answers (4)

GhostCat
GhostCat

Reputation: 140525

Your problem is of a different nature.

I just put down your code in my eclipse NEON (which uses Java8). And your code compiles fine; not showing any problems.

Because Java is smart enough (by now) to understand that you want to compare two int values. It turns the Integer num argument into a primitive type int implicitly. (that is called auto-boxing resp. un-boxing).

So the answer is most likely: you are using an outdated version of eclipse.

Meaning: eclipse has its own Java compiler. Therefore the version of the JRE/JDK you are working with isn't that important when talking about compiler errors given to you. Because those messages come from the built-in eclipse Java compiler.

And when that eclipse Java compiler tells you that Integer can not be converted to int; then the possible explanations are:

  • you are using a version of eclipse from "stone age". To be precise: auto-boxing was added with Java 1.5. So you have an eclipse that either doesn't support Java 1.5 (which seems extremely unlikely!) ...
  • or you are facing some other configuration issue. For example you set your compliance level to Java 1.4 (which doesn't make any sense; but would explain the error message you are looking at).

Long story short: check your version of eclipse; when it is outdated - turn to eclipse.org, and install the latest version of eclipse. If you are using a recent version of eclipse, check your workspace/project settings.

Upvotes: 7

Kamesh Joshi
Kamesh Joshi

Reputation: 390

You cannot compare an Integer data type with an int data type. This is not valid.

You may rewrite your code as described below: 

public class MultipleCopiesString {

  public static void StringCopy(String inp, int num) {

      for (int i=0; i < num;i++){

      }
  }

}

Upvotes: 1

rilent
rilent

Reputation: 722

Try this :

public class MultipleCopiesString {

    public static void stringCopy(String inp, int num) {

        for (int i=0; i < num;i++){

        }
    }

}

Or if you want to use Integer :

public class MultipleCopiesString {

    public static void stringCopy(String inp, Integer num) {

        for (int i=0; i < num.intValue();i++){

        }
    }

}

In Java the 'int' type is a primitive , whereas the 'Integer' type is an object, meaning you cannot use it like you would use a simple int.

Upvotes: 2

Alex Ferretti
Alex Ferretti

Reputation: 191

2 solutions :

  • use an int instead of an Integer
  • use the intValue() method of the Integer class like so : num.intValue()

Upvotes: 3

Related Questions