Why is Binary represented as a String?

Question

So I am quite new to Java and motivated to learn. This question might seem simple but I genuinely don't understand and have searched Google for answers (no luck).

I am converting a decimal into Binary in Java. However, I thought representations of numbers are supposed to be given in data types int, double, and etc.

The code is as follows :

int decimal = 99;
String binary = Integer.toBinaryString(decimal);
System.out.println(binary);

Why is it String binary, should it not be any of the numerical data types?

Answer 1

Internally, all values are stored as binary values. Because it's easier to read, integers are converted into digits for display. Displaying a value as a binary is thus purely a representation issue.

So 99 is internally stored as 01100011. You can display it as a hexadecimal (0x63), a decimal (99), or a binary. But because the numerical value is the same in each case, the only difference is the symbols used to display it, and this symbolic representation is as a String.

Answer 2

The following ints are all equal:

int i = 99;
int j = 0o143;
int k = 0x63;
int l = 0b1100011;

If you want to print them, you have to convert them to a String using a utility method of Integer, or you use number formatting.