算术运算符

2019-08-08 00:00:00 运算符 算术

算术运算符 :  +(正)  – +(加)  –  *  /  %(取余)  前++ 后++ 前– 后– +(连接符)

public class AriTest{

    public static void main(String[] args){
    
        int a = +5;
        System.out.println(a);

        System.out.println("-----------除-------------");

        int num = 10;
        int num2 = num / 4; //2
        System.out.println(num2);

        double num3 = 10 / 4;
        System.out.println("num3=" + num3);//2.0

        double num4 = 10 / (double)4;
        System.out.println("num4=" + num4);

        double num5 = (10 * 1.0) / 4;
        num5 = 10 / 4 * 4;
        num5 = 10 * 4 / 4;
        System.out.println("num5=" + num5);

        System.out.println("-----------取余-------------");

        //用途 : 1.判断一个数是否能被另一个数整除
        System.out.println(0 % 3);//0
        System.out.println(1 % 3);//1
        System.out.println(2 % 3);//2
        System.out.println(3 % 3);//0
        System.out.println(4 % 3);//1
        System.out.println(5 % 3);//2
        System.out.println("-----------------------");
        //思考 :取模的结果的正负和谁有关?和被模数有关
        System.out.println(-4 % 3);//-1
        System.out.println(4 % -3);
        System.out.println(-4 % -3);//-1

        System.out.println("-----------前++ 后++  前-- 后-- -------------");
        
        int n = 10;
        int nn = n++;//先赋值(运算),再自增1
        System.out.println("n=" + n + " nn=" + nn);//n=11 nn=10

        int n2 = 10;
        int nn2 = ++n2;//先自增1,再赋值(运算)
        System.out.println("n2=" + n2 + " nn2=" + nn2);//n2=11 nn2=11

        System.out.println("-------------------------------");

        int n3 = 10;
        int nn3 = n3--;//先赋值(运算),再自减1
        System.out.println("n3=" + n3 + " nn3=" + nn3);//n3 = 9 nn3 = 10

        int n4 = 10;
        int nn4 = --n4;//先自减1,再赋值(运算)
        System.out.println("n4=" + n4 + " nn4=" + nn4);//n4 = 9 nn4 = 9

    }
}

 

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