英文:
How can I access a helper method for a boolean array in my main method?
问题
我正在写作
这是我目前的进展：
import java.util.Scanner;
新的 Boolean[count];
}
我在哪里？
英文:
I am writing
This is what I have so far:
import java.util.Scanner;
ew Boolean[count];
}
}
Where am I g
答案1
得分: 5
Boolean[]和boolean[]不同。将Boolean[] vegetarian = new Boolean[count];改为boolean[] vegetarian = new boolean[count];就可以工作了。
解释：
Boolean是基本类型boolean的包装类。因此，可以这样写：
boolean b1 = true;
Boolean booleanObject = b;
boolean b2 = booleanObject;
这种行为称为自动装箱和拆箱。然而，尽管数组在协变性方面是协变的，但它们只在对象层次结构内是协变的，而不适用于包装类型。这就是Boolean[]不能赋值给boolean[]，反之亦然的原因。
英文:
Boolean[] and boolean[] are not the same. Change Boolean[] vegetarian = new Boolean[count]; to boolean[] vegetarian = new boolean[count]; and it will work.
Explanation:
Boolean is the wrapper-class for the primitive boolean. Thus, one can write
boolean b1 = true;
Boolean booleanObject = b;
boolean b2 = booleanObject;
This behaviour is known as Autoboxing and -unboxing. However, even though arrays are covariant, they are only covariant within the object-hierachy, not to the wrapper types. This is the reason an Boolean[] cannot be assigned to a boolean[] and vice-versa.
答案2
得分: 1
你正在使用布尔值（Boolean），它是一个对象。你不能直接比较布尔对象和布尔基本类型。
尝试使用 getVegetarian.booleanValue()，这会起作用！
if (list[i].booleanValue() == true) {
count++;
}
顺便说一下，你不必写成 getVegetarian.booleanValue()==true，getVegetarian.booleanValue() 就足够了 
英文:
you are using Boolean and that is an object. You cannot directly compare an Boolean object to a boolean primitive.
Try using getVegetarian.booleanValue(), this will work!
if (list[i].booleanValue() == true) {
count++;
}
BTW you don't have to write getVegetarian.booleanValue()==true, getVegetarian.booleanValue() is enough :-)
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