Make a negative number positive in Java

Hi, I'm sure this is a very simple question! I have a Java method in which I'm summing a set of numbers. However, I want any negatives numbers to be treated as positives. So (1)+(2)+(1)+(-1) should equal 5. I'm sure there is very easy way of doing this - I just don't know how!! Any tips would be much appreciated.

From stackoverflow

• Just call Math.abs?

  JB King : Jon Skeet gets another one. ;)

  Zach Scrivena : Note the edge cases, e.g. Math.abs(Integer.MIN_VALUE) = Integer.MIN_VALUE.

• Are you asking about absolute values?

  Math.abs(...) is the function you probably want.

• The concept you are describing is called "absolute value", and Java has a function called Math.abs to do it for you. Or you could avoid the function call and do it yourself:

  number = (number < 0 ? -number : number);
  

  or

  if (number < 0)
      number = -number;
  

  Paul Tomblin : Oh, dilemma time - there are so many equally good answers, that I might as well delete mine. But then I'd lose 40 points, and I'll never catch Jon Skeet if I do that.

  cletus : Sorry -1 for reinventing a standard library call.

  Paul Tomblin : @cletus, did you notice that I had already mentioned the standard library call? Or that in this case, the "reinvent" takes fewer instructions that calling the library?

  simon : Also worth understanding the details behind the library call. Especially if there are side effects to the library call, or performance issues like Paul mentions.

• Use the abs function:

  int sum=0;
  for(Integer i : container)
    sum+=Math.abs(i);
  

• The easiest, if verbose way to do this is to wrap each number in a Math.abs() call, so you would add:

  Math.abs(1) + Math.abs(2) + Math.abs(1) + Math.abs(-1)
  

  with logic changes to reflect how your code is structured. Verbose, perhaps, but it does what you want.

  Dan Dyer : You could make it less verbose with a static import.

• You're looking for absolute value, mate. Math.abs(-5) returns 5...

• You want to wrap each number into Math.abs(). e.g.

  System.out.println(Math.abs(-1));
  

  prints out "1".

  If you want to avoid writing the Math.-part, you can include the Math util statically. Just write

  import static java.lang.Math.abs;
  

  along with your imports, and you can refer to the abs()-function just by writing

  System.out.println(abs(-1));
  

• 1 more

  Why don't you use:

  Ma..ab....

  ... Oh.