68 lines
1.1 KiB
Markdown
68 lines
1.1 KiB
Markdown
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---
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title: If in Go
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---
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# If in Go
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Go's `if` statements are like its `for` loops; the expression need not be surrounded by parentheses
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`(` `)` but the braces `{` `}` are required.
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```go
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func sqrt(x float64) string {
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if x < 0 {
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return sqrt(-x) + "i"
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}
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return fmt.Sprint(math.Sqrt(x))
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}
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```
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Like `for`, the `if` statement can start with a short statement to execute before the condition.
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Variables declared by the statement are only in scope until the end of the `if`.
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```go
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func pow(x, n, lim float64) float64 {
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if v := math.Pow(x, n); v < lim {
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return v
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}
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return lim
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}
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```
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## If and else
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Variables declared inside an `if` short statement are also available inside any of the `else` blocks.
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```go
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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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func pow(x, n, lim float64) float64 {
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if v := math.Pow(x, n); v < lim {
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return v
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} else {
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fmt.Printf("%g >= %g\n", v, lim)
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}
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// can't use v here, though
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return lim
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}
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func main() {
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fmt.Println(
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pow(3, 2, 10),
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pow(3, 3, 20),
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)
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}
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```
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Running the above program produces an output similar to the following output -
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```
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$ go run if.go
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27 >= 20
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9 20
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```
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