java 第3章 运算符

2016-06-24

 

1、HelloWorld.java

package com.HelloWorld;

public class HelloWorld {
    public static void main(String[] args)
    {
        System.out.println("Hello World!");
    }

}

2、变量

package com.Test;

public class Test {
    public static void main(String[] args)
    {
        System.out.println("Define a variable a is ");
        int a; //声明变量a
        a = 5;
        
        System.out.println(a); //打印一个整数a
    }

}

3、运算符

package com.Test;

public class Operator {
    public static void main(String[] args)
    {
        int a,b,c,d;
        a = 6 + 7;
        System.out.println("a = " +a);
        b = a % 5;
        System.out.println("b = " +b);
        c = b++;
        System.out.println("b++后 b = "+b);
        System.out.println("c = "+c);
        d = ++b;
        System.out.println("++b后 b = "+b);
        System.out.println("d = "+d);
    }

}

4、比较运算符

package com.Test;

public class Compare {
    public static void main(String[] args)
    {
        int a = 1;
        double b = 7.2;
        String str1 = "hello";
        String str2 = "CenLiang";
        System.out.println("a等于b: "+(a == b));
        System.out.println("a大于b: "+(a > b));
        System.out.println("a小于等于b: " + (a <= b));
        System.out.println("str1等于str2: "+(str1 == str2));
    }

}

5、逻辑运算符

package com.Test;

public class Logic {
    public static void main(String[] args)
    {
        boolean a = true; // a同意
        boolean b = false; // b反对
        boolean c = false; // c反对
        boolean d = true; // d同意
        
        System.out.println(a&&b);
        System.out.println(a||b);
        System.out.println((!a));
        System.out.println((c^d));
    }

}