Type mismatch with If statement containing bitwise operators

Question

I am new to scala but I am having the problem with the following code:

var c:Int = 0
var j:Int = 0

for( c <- 0 to 100){
  for( j <- 0 to 100){

   /* Check if jth bit in c is set,
    if( (c & (1<<j)) )  // this line is the line where i get the error
    xs :+ (ys(j))   // this is copying element j from list ys to list xs     
  }
}

The error I get is: type mismatch; found : Int required: Boolean

the code (c & (1<<j)) should be shifting 1 left j bits and then bitwise anding the result to the int in the variable c to get a boolean result.

It is entirely possible that I am doing something wrong.. I have been learning Scala fro 3 days and I am very rusty on my java.

Any help would be appreicated

Hunter McMillen Hunter McMillen · Accepted Answer · 2013-04-03T05:47:49

Bitwise operations in Scala (in fact in any language) return a result of type Int, your if expression requires a type of Boolean. Scala doesn't treat Boolean values like C, where you code would work fine.

You can make your expression return a Boolean by testing explicitly for 1:

if((c & (1 << j)) != 0)

Type mismatch with If statement containing bitwise operators

2 Answers