Question

我遇到错误：

java.lang.AssertionError: expected: learning.java.advancedoop2.MyComplex<(2.0+10.0i)> but was: learning.java.advancedoop2.MyComplex<(2.0+10.0i)>
Expected :learning.java.advancedoop2.MyComplex<(2.0+10.0i)> 
Actual   :learning.java.advancedoop2.MyComplex<(2.0+10.0i)>

我现在正在处理MyComplex类，如3.1所示： http://www.ntu.edu.sg/home/ehchua/programming/java/J3f_OOPExercises.html#zz-2

这是相关代码的一部分：

package learning.java.advancedoop2;

public class MyComplex {

    private double real = 0.0;
    private double imag = 0.0;

public MyComplex() {

}

    public MyComplex add(MyComplex right) {
        this.imag += right.imag;
        this.real += right.real;
        return this;
    }
}

我尝试进行测试，当我运行它们时，我遇到的错误是潜在的，这是我的测试代码的一部分：

@Test
public void add() {

    MyComplex myComplexFirst = new MyComplex(1, 5);
    MyComplex myComplexSecond = new MyComplex(1, 5);
    MyComplex myComplexThird = new MyComplex(myComplexFirst.getReal() + myComplexSecond.getReal(), myComplexFirst.getImag() + myComplexSecond.getImag());
    myComplexFirst.add(myComplexSecond);
    MyComplex newComplex = myComplexFirst;
    assertEquals(newComplex, myComplexThird);
}

Answer 1

您是否在自定义类中覆盖了equals方法？

如果没有，默认行为是比较引用。这将解释您收到的错误消息。

这令人困惑，因为您已经覆盖了toString方法，该方法将两个实例显示为具有相同的值。

Answer 2

您需要重写equals方法，以便Java知道如何比较两个MyComplex对象。现在，它不知道您要基于real和imag的值来比较对象。

@Override
public boolean equals(Object o) { 

    // If the object is compared with itself then return true   
    if (o == this) { 
        return true; 
    } 

    // Check if o is an instance of MyComplex
    if (!(o instanceof MyComplex)) { 
        return false; 
    } 

    // typecast o to MyComplex so that we can compare data members  
    MyComplex c = (MyComplex) o; 

    // Compare the data members and return accordingly  
    return Double.compare(real, c.getReal()) == 0
            && Double.compare(imag, c.getImag()) == 0; 
}

AssertionError-虚数和实数加法器

2 个答案: