Go語言傳遞指針到函數

Go編程語言允許傳遞一個指針到函數中。 為此，只需將函數的參數聲明為指針類型。
看看下麵一個簡單的例子，傳遞了兩個指針給一個函數，並在函數裏面改變它們的值，這個值反映在調用函數中：

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100
   var b int= 200

   fmt.Printf("Before swap, value of a : %d\n", a )
   fmt.Printf("Before swap, value of b : %d\n", b )

   /* calling a function to swap the values.
   * &a indicates pointer to a ie. address of variable a and
   * &b indicates pointer to b ie. address of variable b.
   */
   swap(&a, &b);

   fmt.Printf("After swap, value of a : %d\n", a )
   fmt.Printf("After swap, value of b : %d\n", b )
}

func swap(x *int, y *int) {
   var temp int
   temp = *x    /* save the value at address x */
   *x = *y      /* put y into x */
   *y = temp    /* put temp into y */
}

當上述代碼編譯和執行時，它產生以下結果：

Before swap, value of a :100
Before swap, value of b :200
After swap, value of a :200
After swap, value of b :100