我是编程新手,我想知道在实例化对象时哪里出错了。下面是代码:
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);
}
}
您的代码中没有 "Sample "类。 您声明的是一个私有方法。
// 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;
}
在当前代码段中,您需要实例化Testing
类并使用Sample
方法。请注意,在类定义的前面有关键字 class,本例中是 class 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);
}
}
但这并没有什么意义,你的 Sample
方法总是返回 3
。
你是不是想做这样的事情 :
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);
}
}