2018-09-15

1、算术运算符：
+：加
-：减
*：乘
/：除
+=：例如 a += b; –> a = a + b;
-=：例如 a -= b; –> a = a - b;
=：例如 a = b; –> a = a * b;
/=：例如 a /= b; –> a = a / b;

public class OperatorTest01 {

    public static void main(String[] args) {

        // 算术运算符

        // 先声明
        int a;
        int b;
        int sum;
        int subtract;
        int multiply;
        int divide;

        // 后调用
        a = 1;
        b = 2;
        sum = a + b; // 加
        subtract = a - b; // 减
        multiply = a * b; // 乘
        divide = a / b; // 除

        // 输出
        System.out.println("加，sum = " + sum);
        System.out.println("减，subtract = " + subtract);
        System.out.println("乘，multiply = " + multiply);
        System.out.println("除，divide = " + divide);

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

        a += b; // a = a + b;
        System.out.println("Run... a += b, a = " + a + ", b = " + b);

        a -= b; // a = a - b;
        System.out.println("Run... a -= b, a = " + a + ", b = " + b);

        a *= b; // a = a * b;
        System.out.println("Run... a *= b, a = " + a + ", b = " + b);

        a /= b; // a = a / b;
        System.out.println("Run... a /= b, a = " + a + ", b = " + b);

        String s = "我爱你";
        System.out.println(s);

        s += ",北京"; // 字符串拼接
        System.out.println(s);

    }

}

javac -encoding utf-8 -g OperatorTest01.java

java OperatorTest01

PgUp，PaDown查找之前的输入
Tab 补齐字符