java中减法命令_java中减法和乘法的性能比较

#1 :32

#2 :-32

#3 :-32

#4 * (-1) running time is：115391

#5 0- running time is：22911

性能约好８０％

在android自定义view的过程中，注意使用。

public class SubMultiplicationPerformanceTest {

public static void main(String[] args) {

// TODO Auto-generated method stub

long startTime = 0L;

long endTime = 0L;

//求相反数

System.out.println("#1 :"+getScrollDistance());

System.out.println("#2 :"+getScrollDistance() * (-1));

System.out.println("#3 :"+(0 - getScrollDistance()));

//乘法

startTime = System.nanoTime();

for (int i = 0; i < 1000; i++) {

int result = getScrollDistance() * (-1);

}

endTime = System.nanoTime();

System.out.println("#4 * (-1) running time is："+(endTime-startTime));

//减法

startTime = System.nanoTime();

for (int i = 0; i < 1000; i++) {

int result = (0 - getScrollDistance());

}

endTime = System.nanoTime();

System.out.println("#5 0- running time is："+(endTime-startTime));

}

private static int getScrollDistance() {

return 32;

}

}