| Go supports _constants_ of character, string, boolean, and numeric values. | ||
package main |
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import ( |
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"fmt" |
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"math" |
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) |
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| `const` declares a constant value. | const s string = "constant" |
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func main() { |
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fmt.Println(s) |
constant |
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| A `const` statement can appear anywhere a `var` statement can. | const n = 500000000 |
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| Constant expressions perform arithmetic with arbitrary precision. | const d = 3e20 / n |
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fmt.Println(d) |
6e+11 |
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| A numeric constant has no type until it's given one, such as by an explicit conversion. | fmt.Println(int64(d)) |
600000000000 |
| A number can be given a type by using it in a context that requires one, such as a variable assignment or function call. For example, here `math.Sin` expects a `float64`. | fmt.Println(math.Sin(n)) |
-0.28470407323754404 |
} |