java代码练习第2课

翠花，上代码！

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test011.java

public class test011
{
  int x = 45;
  static int y = 90;

  public static void main(String[] args)
  {
    test011 temp = new test011();
    System.out.println("x为类的实例变量：" +  temp.x);

    System.out.println("y为类的静态变量:" + test011.y);
  }
}

test012.java

public class test012
{
  static int times = 3;

  public static void main(String[] args)
  {
    int times = 4;
    System.out.println("times的值为：" + times); //局部变量，在{}内部优先
  }
}

test013.java

public class test013
{
  public static void main(String[] args)
  {
    int a,b,c;

    a = 15;
    c = b = a + 4;  //不建议这样写，

    System.out.println("a=" + a);
    System.out.println("b=" + b);
    System.out.println("c=" + c);
  }
}

test014.java

public class test014
{
  public static void main(String[] args)
  {
    float number1 = 45.56f;
    int number2 = 152;

    System.out.println("加法：" + (number1 + number2));
    System.out.println("减法：" + (number1 - number2));
    System.out.println("乘法：" + (number1 * number2));
    System.out.println("除法：" + (number1 / number2));
  }
}

test015.java

public class test015
{
  public static void main(String[] args)
  {
    int number1 = 4;
    int number2 = 5;

    System.out.println(">:" + (number1 > number2));
    System.out.println("<:" + (number1 < number2));
    System.out.println("==:" + (number1 == number2));
    System.out.println("!=:" + (number1 != number2));
    System.out.println(">=:" + (number1 >= number2));
    System.out.println("<=:" + (number1 >= number2));


  }
}

test016.java

public class test016
{


  public static void main(String[] args)
  {
    int a = 2;
    int b = 5;

    boolean result1 = ((a>b) && (a!=b));  // && 条件都成立时，为true
    boolean result2 = ((a>b) || (a!=b)); // 条件一方成立，即为true

    System.out.println(result1);
    System.out.println(result2);


  }


}

test017.java

public class test017
{
  public static void main(String[] args)
  {
    int a = 20;
    int b = 45;
    boolean result1;

    if(a < b)
    {
      result1 = true;
    }
    else 
    {
      result1 = false;
    }

    int x = 20;
    int y = 45;

    boolean result2 = x < y ? true:false;  //三元运算符，等价与if else

    System.out.println(result1);
    System.out.println(result2);
  }
}

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