如何在java中实例化一个对象?
作者:互联网
我是编程新手,我想知道在实例化对象时我出错了.以下是代码:
public class Testing{
private int Sample(int c)
{
int a = 1;
int b = 2;
c = a + b;
return c;
}
public static void main(String []args)
{
Sample myTest = new Sample();
System.out.println(c);
}
}
解决方法:
您的代码中没有Sample类.您声明的是私有方法.
// private method which takes an int as parameter and returns another int
private int Sample(int c)
{
int a = 1;
int b = 2;
c = a + b;
return c;
}
使用当前代码段,您需要实例化Testing类并使用Sample方法.请注意,您的类定义前面是关键字class,在本例中为类Testing.
public class Testing{
private int Sample(int c)
{
int a = 1;
int b = 2;
c = a + b;
return c;
}
public static void main(String []args)
{
Testing t = new Testing(); // instantiate a Testing class object
int result = t.Sample(1); // use the instance t to invoke a method on it
System.out.println(result);
}
}
但这并没有多大意义,您的Sample方法总是返回3.
你想做这样的事情:
class Sample {
int a;
int b;
Sample(int a, int b) {
this.a = a;
this.b = b;
}
public int sum() {
return a + b;
}
}
public class Testing {
public static void main(String[] args) {
Sample myTest = new Sample(1, 2);
int sum = myTest.sum();
System.out.println(sum);
}
}
标签:java,instantiation 来源: https://codeday.me/bug/20190926/1818409.html