|char||unsigned Unicode||16||2||4:5||'\u0000'  aka Character. MIN_VALUE||'\uffff' [216-1] aka Character. MAX_VALUE||Unicode chars are twice as big as C’s.|
|byte||signed||8||1||2:3||-128 [-27] aka Byte. MIN_VALUE||+127 [27-1]aka Byte. MAX_VALUE||Bytes are signed, so half the usual 255 range.|
|short||signed||16||2||4:5||-32,768 [-215] aka Short. MIN_VALUE||+32,767 [215-1] aka Short. MAX_VALUE||32K|
|int||signed||32||4||9:10||-2,147,483,648 [-231] aka Integer.MIN_VALUE aka -2 gig, roughly -2 billion||+2,147,483,647 [231-1] aka Integer. MAX_VALUE. aka 2 gig, roughly 2 billion||2 gig|
|long||signed||64||8||1:19||-9,223,372,036,854,775,807 [-263] aka Long. MIN_VALUE about -9×1018||9,223,372,036,854,775,808 [+263-1] aka Long. MAX_VALUE about 9×1018||9 exabytes, or 9 billion gig|
|float||signed exponent and mantissa||32||4||7||±1.40129846432481707e-45 aka Float. MIN_VALUE||±3.40282346638528860e+38 aka Float.
or roughly ±2127
with about 7 significant digits of accuracy.
A float can exactly represent integers
in the range -224 to +224.
|rough, compact float|
|double||signed exponent and mantissa||64||8||16||±4.94065645841246544e-324 aka Double. MIN_VALUE||±1.79769313486231570e+308 aka Double.
or roughly ±21023
with 15 significant digits of accuracy, almost 16 with 15.95 significant digits.
A double can exactly represent integers
in the range -253 to +253.
|high precision float|
Similarly you normally use int in preference to short, char or byte except in arrays or Object fields, even when you don’t need the extra range because modern computer hardware is based around 32-bit quantities.
For small 8-bit quantities you can use byte either signed or unsigned. For 16-bit unsigned, use char, and 16-bit signed use short. Normally you use int, except for arrays or objects, since ints are generally faster, though they take more room.
If the value is a measurement of a physical quantity, use a double or float depending on the accuracy required. double is equivalent to scientific notation, allowing very large or very small numbers with only 15 significant digits. Floating point arithmetic is not precise for a number of reasons. On the other hand, it gives you tremendous range.
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