initializing a boolean array in java
JavaArraysInitializationJava Problem Overview
I have this code
public static Boolean freq[] = new Boolean[Global.iParameter[2]];
freq[Global.iParameter[2]] = false;
could someone tell me what exactly i'm doing wrong here and how would i correct it? I just need to initialize all the array elements to Boolean false. thank you
Java Solutions
Solution 1 - Java
> I just need to initialize all the array elements to Boolean false.
Either use boolean[] instead so that all values defaults to false:
boolean[] array = new boolean[size];
Or use Arrays#fill() to fill the entire array with Boolean.FALSE:
Boolean[] array = new Boolean[size];
Arrays.fill(array, Boolean.FALSE);
Also note that the array index is zero based. The freq[Global.iParameter[2]] = false; line as you've there would cause ArrayIndexOutOfBoundsException. To learn more about arrays in Java, consult this basic Oracle tutorial.
Solution 2 - Java
The array will be initialized to false when you allocate it.
All arrays in Java are initialized to the default value for the type. This means that arrays of ints are initialised to 0, arrays of booleans are initialised to false and arrays of reference types are initialised to null.
Solution 3 - Java
Arrays in Java start indexing at 0. So in your example you are referring to an element that is outside the array by one.
It should probably be something like freq[Global.iParameter[2]-1]=false;
You would need to loop through the array to initialize all of it, this line only initializes the last element.
Actually, I'm pretty sure that false is default for booleans in Java, so you might not need to initialize at all.
Best Regards
Solution 4 - Java
They will be initialized to false by default. In Java arrays are created on heap and every element of the array is given a default value depending on its type. For boolean data type the default value is false.
Solution 5 - Java
public static Boolean freq[] = new Boolean[Global.iParameter[2]];
Global.iParameter[2]:
It should be const value
Solution 6 - Java
The main difference is that Boolean is an object and boolean is an primitive.
- Object default value is null;
- boolean default value is false;