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43 lines
1.1 KiB
Go
43 lines
1.1 KiB
Go
// Go supports <em><a href="http://en.wikipedia.org/wiki/Pointer_(computer_programming)">pointers</a></em>,
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// allowing you to pass references to values and records
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// within your program.
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package main
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import "fmt"
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// We'll show how pointers work in contrast to values with
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// 2 functions: `zeroval` and `zeroptr`. `zeroval` has an
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// `int` parameter, so arguments will be passed to it by
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// value. `zeroval` will get a copy of `ival` distinct
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// from the one in the calling function.
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func zeroval(ival int) {
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ival = 0
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}
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// `zeroptr` in contrast has an `*int` parameter, meaning
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// that it takes an `int` pointer. The `*iptr` code in the
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// function body then _dereferences_ the pointer from its
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// memory address to the current value at that address.
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// Assigning a value to a dereferenced pointer changes the
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// value at the referenced address.
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func zeroptr(iptr *int) {
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*iptr = 0
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}
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func main() {
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i := 1
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fmt.Println("initial:", i)
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zeroval(i)
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fmt.Println("zeroval:", i)
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// The `&i` syntax gives the memory address of `i`,
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// i.e. a pointer to `i`.
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zeroptr(&i)
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fmt.Println("zeroptr:", i)
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// Pointers can be printed too.
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fmt.Println("pointer:", &i)
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}
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