Java 如何从另一个类执行(调用)一个类的函数?
我有两个类:“Add.java”和“Subtract.java”。我想在“subfn”方法(类减法中使用“addfn”方法(类的Add)的结果。我该怎么做 Add.javaJava 如何从另一个类执行(调用)一个类的函数?,java,bluej,Java,Bluej,我有两个类:“Add.java”和“Subtract.java”。我想在“subfn”方法(类减法中使用“addfn”方法(类的Add)的结果。我该怎么做 Add.java public class Add { public double a, b; public double addfn(double a, double b) { return (a+b); } } public class Subtract { double c, d;
public class Add
{
public double a, b;
public double addfn(double a, double b)
{
return (a+b);
}
}
public class Subtract
{
double c, d;
public double subfn(double d)
{
//
//I want the "addfn" from class "Add" to accept the variables *a* and *b*
//and then use "subfn" to use the result of "addfn" and assign it to *c*
//
Add obj1 = new Add();
//Can I somehow access the "addfn" method here?
c = a+b; //and then assign its result to c here?
return (c-d);
}
}
Subtract.java
public class Add
{
public double a, b;
public double addfn(double a, double b)
{
return (a+b);
}
}
public class Subtract
{
double c, d;
public double subfn(double d)
{
//
//I want the "addfn" from class "Add" to accept the variables *a* and *b*
//and then use "subfn" to use the result of "addfn" and assign it to *c*
//
Add obj1 = new Add();
//Can I somehow access the "addfn" method here?
c = a+b; //and then assign its result to c here?
return (c-d);
}
}
我尝试用类减法扩展类Add,如下所示:
public class Subtract extends Add
但Java只是将空值分配给a和b,因此c总是变成0。它也不能让我从Add类访问“addfn”
我该怎么做?谢谢
编辑:谢谢你的回答,但是我怎样才能从另一个类运行一个函数呢?我如何能够立即连续运行这两个函数?再次感谢。在您的
添加
类中,行公共双a、b
什么也不做,因为addfn
方法只添加并返回方法参数
Add obj1 = new Add();
c = obj1.addfn(obj1.a,obj1.b);
return (c-d);
由于Subtract
扩展了Add
,因此可以直接使用addfn
public double subfn(double d)
{
c = addfn(5+10);
return (c-d);
}
a和b变量存在于类add中,现在开始。他只是问如何访问函数,不是变量,而是。。。