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147 lines (123 loc) · 4.45 KB
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public class Test3 {
public static void main(String[] args) {
// 46天,包含了几周零几天
int weeks = 46 / 7;
int days = 46 % 7;
System.out.println(weeks + "\t" + days);
System.out.println("---");
//商场活动100当做120花;。 420元,付多少钱?
int money = (420 / 120) * 100 + 420 % 120;
System.out.println(money);
System.out.println("---");
/*输入张三成绩,与李四(80) 。输出 张三是否比李四高
Scanner input = new Scanner(System.in) ;
System.out.println("请输入张三成绩:");
int zsScore = input.nextInt();
System.out.println( zsScore>80 );//80
*/
//int num ; num*3 num+num1
System.out.println((2 + (43 % 6)) > ((10 / 3) * 2));
System.out.println(3 >= 3);
System.out.println("---------");
//输入五位数,求各个位数之和
int num = 12345;
int geWei = num / 1 % 10;//12345->5
int shiWei = num / 10 % 10;//12345->1234->4
int baiWei = num / 100 % 10; //12345 ->123 ->3
int qianWei = num / 1000 % 10; //12345->12 ->2
int wanWei = num / 10000 % 10; //12345 ->1 ->1
System.out.println(geWei + shiWei + baiWei + qianWei + wanWei);
//通项:num任一一位 ,num /所在位数的最小值 % 10 ;
System.out.println();
//两个数交换
int num1 = 10;//30
int num2 = 20;
/*通过 中间变量实现
int temp =num1;
num1 =num2;
num2 = temp ;
// num1 = num2 ;
// num2 = num1 ;
*/
/*数学加减(如果数字很大,可能溢出)
num1 = num1 + num2 ;//30
num2 = num1 - num2 ;//10
num1 = num1 - num2 ;//20
*/
//位运算(效率最高)
num1 = num1 ^ num2;
num2 = num1 ^ num2;
num1 = num1 ^ num2;
System.out.println(num1);
System.out.println(num2);
System.out.println("------------");
int max = Integer.MAX_VALUE;//int最大值
int min = Integer.MIN_VALUE;//int最小值
System.out.println("最大值:" + max);
System.out.println("最大值+1:" + (max + 1));
System.out.println("最小值:" + min);
System.out.println("最小值-1:" + (min - 1));
System.out.println("--------");
System.out.println(10 % -3);
System.out.println(-10 % -3);
System.out.println(10 % 3);
System.out.println(-10 % 3);
System.out.println("---");
System.out.println(3 != 2);
System.out.println("---");
//
System.out.println(2 < 1 && 1 / 0 == 0);//假 且。。。-> 假
System.out.println(2 > 1 || 1 / 0 == 0);//真 或 ... ->真
/*
System.out.println(2<1 & 1/0==0);
System.out.println(2>1 | 1/0==0);
*/
int myNum = 2;
//myNum = myNum + 10 ;
myNum += 10;
System.out.println(myNum);
int sum = 100;
// sum = sum + myNum ;
sum += myNum;
System.out.println(sum);
System.out.println("--------");
// int i = 10 ;
// i = i +1 ;
// i += 1 ;
// i++ ; //i--;
// ++i ; //--i ;
// System.out.println(i);
// i++: 先用 后加
// int i = 10 ;
// System.out.println(i++);//11
// System.out.println(i++);//12
// System.out.println(i++);//13
// System.out.println(i);//13
//
// --i:先减后用
int j = 10;
System.out.println(--j); //9
System.out.println(--j);//8
System.out.println(--j);//7
System.out.println(j);//
System.out.println("----");
// byte b1 = 10 ;// int
// float f = 123.4f ;//double
// 整数 = +=内置转换器
byte b1 = 100;
byte b2 = 100;
// b2 = b1 + b2 ; //特例 byte int 的整数情况, byte +byte ,short +short ->int
//byte = byte + byte ;
//-128 -- 127 = -128 -- 127 + -128 -- 127
// -128 -- 127 = -256 -- 254
b2 += b1;//b2 = b2 + b1 ;
System.out.println("--------");
String str1 = "abc";
String str2 = "abc";
//System.out.println( str1 == str2); //类和对象,引用问题
//System.out.println( str1.equals(str2));
System.out.println("--------");
String result = 10 > 20 ? "hello" : "world";
System.out.println(result);
}
}