定義：
內部方法的使用：
沒有這個的範例：
class Pwr { double b; int e; double val; Pwr(double base, int exp) { b = base; e = exp; val = 1; if (exp == 0) return; for (; exp > 0; exp--) val = val * base; } double get_pwr() { return val; } }
明確使用此：
class Pwr { double b; int e; double val; Pwr(double b, int e) { this.b = b; this.e = e; this.val = 1; if (e == 0) return; for (; e > 0; e--) this.val = this.val * b; } double get_pwr() { return this.val; } }
何時使用此：
當名稱與局部變數或參數衝突時，對於存取實例變數很有用。
在建構函式方法中，引用正在建構的物件。
class Pwr { double b; int e; double val; Pwr(double base, int exp) { this.b = base; this.e = exp; this.val = 1; if (exp == 0) return; for (; exp > 0; exp--) this.val = this.val * base; } double get_pwr() { return this.val; } } class DemoPwr { public static void main(String args[]) { Pwr x = new Pwr(4.0, 2); Pwr y = new Pwr(2.5, 1); Pwr z = new Pwr(5.7, 0); System.out.println(x.b + " raised to the " + x.e + " power is " + x.get_pwr()); System.out.println(y.b + " raised to the " + y.e + " power is " + y.get_pwr()); System.out.println(z.b + " raised to the " + z.e + " power is " + z.get_pwr()); } }
說明：
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