如何在方法中打印结果？

Question

我需要打印出power2方法的结果。如何将它放在变量long a中？ long a = power2（d，n）;

部分出现错误

public class homework {
public static void main(String[] args) {
long starttime = System.nanoTime();
long a = power2(d , n);
long t = System.nanoTime() - starttime;
System.out.println("result1():" + a + ": " + t + "ns");
}
public static double power2(double d, long n) {
double r = 1;
while(n != 0) {
    if(n%2 == 1) {
        r*=d;
    }
    n = n >> 1;
    d = d * d;
}
return r;
}



}

Answer 1

如此简单：

public class homework {

public static void main(String[] args) {
     long starttime = System.nanoTime();
     long a = power2(TheDoubleVariable, The LongVariable);
     long t = System.nanoTime() - starttime;
     System.out.println("result1():" + a + ": " + t + "ns");
}

public static double power2(double d, long n) {
    double r = 1;
    while(n != 0) {
        if(n%2 == 1) {
            r*=d;
        }
    n = n >> 1;
    d = d * d;
    }
    return r;
    }
}