你怎么称呼这种赋值：float aFloat = 4.f;

Question

I am trying to figure how do you call this, I thought of "implicit datatypes" but it seems this really isn't what I imagined.

I also want to know all of the possibilities in Java, like I know you can do it for other numerical values, like bytes, integers, longs, etc. I'd search by myself but I still don't know how to define this sort of numerical variable assignment, or how to name it.

I was just curious about this but I still really want to know!

Thanks in advance.

Answer 1

Explicit Numerals / Numeric Literals

In your example, it's really not "implicit". Quite the reverse.

Here's more on primitive types and their notations (examples pasted below) from the official Java Tutorials , and some tricks you need to know about floats .

You may also want to learn more about conversions, promotions and narrow-casting .

Examples:

int    decVal = 26;      // The number 26, in decimal
int    octVal = 032;     // The number 26, in octal
int    hexVal = 0x1a;    // The number 26, in hexadecimal
int    binVal = 0b11010; // The number 26, in binary
double d1     = 123.4;
double d2     = 1.234e2; // same value as d1, but in scientific notation
float  f1     = 123.4f;

using underscores (since Java 7)

long  creditCardNumber     = 1234_5678_9012_3456L;
long  socialSecurityNumber = 999_99_9999L;
float pi                   = 3.14_15F;
long  hexBytes             = 0xFF_EC_DE_5E;
long  hexWords             = 0xCAFE_BABE;
long  maxLong              = 0x7fff_ffff_ffff_ffffL;
byte  nybbles              = 0b0010_0101;
long  bytes                = 0b11010010_01101001_10010100_10010010;

Answer 2

I agree with haylem, it is not implicit.

You asked for other numerical types examples:

Integer types:

073 (leading zero, octal)
123l (long)
0xFF (hex)

Floating point:

1.1E-3 (double)
1e10f (float)