2017
07-15

# float浮点数

Name

float浮点数

Examples

float a; // Declare variable ‘a’ of type float

a = 1.5387; // Assign ‘a’ the value 1.5387

float b = -2.984; // Declare variable ‘b’ and assign it the value -2.984

float c = a + b; // Declare variable ‘c’ and assign it the sum of ‘a’ and ‘b’ float f1 = 0.0;

for (int i = 0 ; i < 100000; i++) {

f1 = f1 + 0.0001; // Bad idea! See below.

}

println(f1);

float f2 = 0.0;

for (int i = 0; i < 100000; i++) {

// The variable ‘f2’ will work better here, less affected by rounding

f2 = i / 1000.0; // Count by thousandths

}

println(f2);

Description

Data type for floating-point numbers, e.g. numbers that have a decimal point.

Floats are not precise, so adding small values (such as 0.0001) may not always increment precisely due to rounding errors. If you want to increment a value in small intervals, use an int, and divide by a float value before using it. (See the second example above.)

Floating-point numbers can be as large as 3.40282347E+38 and as low as -3.40282347E+38. They are stored as 32 bits (4 bytes) of information. The float data type is inherited from Java; you can read more about the technical details here and here.

Processing supports the double datatype from Java as well. However, none of the Processing functions use double values, which use more memory and are typically overkill for most work created in Processing. We do not plan to add support for double values, as doing so would require increasing the number of API functions significantly.

floating-point 数字的数据类型, 例如具有小数点的数字。

Syntax

float var

float var = value

Parameters

 var variable name referencing the float value any floating-point value

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