💖 单选题

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💖 填空题

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💖 判断题

💖 程序阅读题

1. 读代码写结果

class A
{
	int m = 5;

	void zengA(int x)
	{
		m = m + x;
	}

	int jianA(int y)
	{
		return m - y;
	}
}

class B extends A
{
	int m = 3;

	int jianA(int z)
	{
		return super.jianA(z) + m;
	}
}

public class Test
{
	public static void main(String[] args)
	{
		A a1 = new A();
		A a2 = new A();
		B b = new B();
		A t = (A) b;
		A a3, a4;
		a3 = b;
		a4 = a1;
		a1.zengA(5);
		a3.zengA(6);
		b.m = 4;
		System.out.println(a1.m); // 【代码 1】
		System.out.println(a2.m); // 【代码 2】
		System.out.println(a3.m); // 【代码 3】
		System.out.println(a4.m); // 【代码 4】
		System.out.println(a3.jianA(1)); // 【代码 5】11-1+4 = 14
	}
}

2. 读代码写结果

abstract class A
{
	public abstract double f(double x, double y);
}

class B extends A
{
	double m;

	public double f(double a, double b)
	{
		return a * b + m;
	}
}

public class E
{
	public static void main(String args[])
	{
		B b = new B();
		A a = b;
		b.m = 2.0;
		System.out.println(a.f(2.0, 3.0)); // 【代码 1】 2 * 3 + 2 = 8.0
	}
}

3. 读代码写结果

class A
{
	static int m = 5;

	void zengA(int x)
	{
		m = m + x;
	}
}

public class E
{
	public static void main(String args[])
	{
		A a1 = new A();
		A a2 = new A();
		a2.zengA(5);
		System.out.println(a1.m); // 【代码 1】
		System.out.println(a2.m); // 【代码 2】
	}
}

4. 读代码写结果

class A
{
	int x = 100;
	double y = 200.3;

	A(int x)
	{
		x = x;
	}

	A(double y)
	{
		this.y = y;
	}

	double B()
	{
		return x + y;
	}
}

public class Test
{
	public static void main(String[] args)
	{
		A a1 = new A(-80);// 构造方法：细节 x=x，相当于啥也没干
		System.out.println(a1.B()); // 【代码 1】100+200.3 = 300.3
		A a2 = new A(60.5);
		System.out.println(a2.B()); // 【代码 2】
	}
}

5. 读代码写结果

interface A
{
	public double f(double x, double y);
}

class B implements A
{
	double m;

	public double f(double a, double b)
	{
		return a * b + m;
	}
}

public class E
{
	public static void main(String args[])
	{
		B b = new B();
		A a = b;
		b.m = 2.0;
		System.out.println(a.f(2.0, 3.0));// 2 * 3 + 2 = 8
	}
}