浮点文字语法

Question

Following these two lines:

float f1 = 2E10f;
float f2 = 0x2P10f;

The output is:

2.0E10
2048.0

Respectively.

So my question is:

What is E10 and P10 equivalent to in decimals?

I think E10 equivalent to 10 ¹⁰ , is that true?

Answer 1

E and P are exponent indicators in floating point literals . You can also express number in decimal (base 10) or hexadecimal (base 16).

• 2E10f is 2*10^10 (decimal base with exponent indicator)
• 0x2P10f is 2*2^10 (hexadecimal base with binary exponent indicator)

Answer 2

I think E10 equivalent to 10^10(10 to the power of 10), is that true?

Yes. Proof:

Use BigDecimal#toPlainString :

System.out.println(new BigDecimal(2.0E10).toPlainString());

Output will be 20000000000.

Meaning that E10 is 10 ¹⁰ . ∎