小编Inv*_*r22的帖子

出于好奇,我想知道以下哪一项会更快地执行.语言是Java.

int num = -500;
int num2 = 0;

while( Math.abs(num) > num2 )
    num2 ++;

要么

int num = -500;
int num2 = 0;
num = Math.abs(num);

while( num > num2 )
    num2 ++;

基本上我想知道是否为while循环的每次迭代调用'Math.abs',或者是否在后台进行了一些代码优化？

谢谢!

在过去的几天里,我一直在尝试使用Java中的Classes,从youtube上的"TheNewBoston"和java文档中了解它们.

我已经创建了以下场景,并就我的一些问题寻求你们的(女孩们)专业批评和深入了解.

有两个类,person和person_financial,分别是基类和子类.

人类:

public class person {

private String name;
private String sex;
private int age;
private double height;
private double weight;
private double intelligence;

// person constructor arguments order: name, height, weight, age, sex, intelligence
public person(){
    this("noname",0,0,0,"undefined",5);
}
public person(String n){
    this(n,0,0,0,"undefined",5);
}
public person(String n, double h){
    this(n,h,0,0,"undefined",5);
}
public person(String n, double h, double w){
    this(n,h,w,0,"undefined",5);
}
public person(String n, double h, double w, int a){
    this(n,h,w,a,"undefined",5);
}
public person(String n, double h, double w, …