自增自减，幂运算，逻辑运算符、短路运算，位运算，字符串连接符，三元运算符复习
package com.kun.base;public class Demo02 {public static void main(String[] args) {int a = 5;int b = a--;//执行完这行代码前先赋值b再自减System.out.println(a);//4 执行完自减后输出的aint c = --a;//执行完这行代码前先自减再复制cSystem.out.println(a);//3System.out.println(b);//5System.out.println(c);//3System.out.println("==========================");double pow = Math.pow(4,2);//幂运算 2^4 2*2*2*2=16System.out.println(pow);System.out.println("==========================");//逻辑运算符boolean a1 = true;boolean b1 = false;System.out.println("a1 && b1:"+(a1&&b1));//逻辑与运算：两个变量都为真，结果才为trueSystem.out.println("a1 || b1:"+(a1||b1));//逻辑或运算：两个变量有一个为真，则结果才为trueSystem.out.println("!(b1 && a1):"+!(b1&&a1));//如果为真，则变为假，如果是假则变为真//短路运算int c1 = 6;boolean d1 = (c1<5)&&(c1++<5);//c1<5判定为false 直接跳过c1++<5System.out.println(d1);//falseSystem.out.println(c1);//6未执行c1++(短路运算)int c2 = 6;boolean d2 = (c2>5)&&(c2++<5);//c1>5判定为true 继续执行c2++<5判定为false 输出结果为falseSystem.out.println(d2);//falseSystem.out.println(c2);//7执行完c2++后输出c2System.out.println("==========================");/*位运算A = 0011 1100B = 0000 1101--------------------------------A&B = 0000 1100 有0为0无0为1A|B = 0011 1101 有1为1无1为0A^B = 0011 0001 相同为0反之为1~B = 1111 0010 取反2*8 = 16 2*2*2*2效率极高！！！<< *2>> /20000 0000 00000 0001 10000 0010 20000 0011 30000 0100 40000 1000 80001 0000 16*/System.out.println(2<<4);//2*2*2*2*2System.out.println(2>>1);//2/1System.out.println("==========================");int a2 = 1;int b2 = 2;//字符串连接符 + ，String类System.out.println(a2+b2);System.out.println(""+a2+b2);//此处“""”为字符串所有“+”为字符串连接符System.out.println(a2+b2+"2");//现将a2+b2求和再连接字符串“2”System.out.println("==========================");//三元运算符// x ? y : z （如果x==true,则结果为y,否则结果为z）int score1 =50;int score2 =70;String type1 = score1 <60 ?"不合格":"合格";System.out.println("1号成绩"+type1);String type2 = score2 <60 ?"不合格":"合格";System.out.println("2号成绩"+type2);}
}
