import java.math.BigInteger;
class Threeyaun{
public static void main(String[] args){
//_______________________________________________________________________________
/* int age =100 ;
if (age <=50){
System.out.println("小");
}
else{
System.out.println("大");
}
//
System.out.println(age <=50 ?"大" : "小");
int a= 1,b = 2 ,c = 3;//定义一个字符串
int max = 0 ;
if (a>b){
if(a > c){
max=a;
}
else{
max = c;
}
}
else{
if(b>c){
max =b;
}
else{
max=c;
}
}
System.out.println("max is "+ max);
//用三元运算符表示的话 a ? b :c ;
System.out.println("max is "+ (a > b ? a:b));// 如果a > b ? 取出a
System.out.println("max2 is "+ (a > b ? (a>c ? a:c) : (b>c ? b:c)));//先判断a > b ? ，如果a>b执行(a>c ? a:c)，否则: (b>c ? b:c)
//_______________________________________
//四个数表示大小//(a > b ? (a>c ? a:c) : (b>c ? b:c)))
/* int a= 1,b = 5 ,c = 3 ,d=2; //a>b,判断a>c 判断(a>c ? a:c)>d?
System.out.println("max2 is "+ (a > b ? ((a>c ? a:c)>d? (a>c ? a:c):d ) : ((b>c ? b:c)>d ?(b>c ? b:c):d ) ));
}
} */
//四个数相比较的时候，比较大小
/* class demos{
public static void main (String [] args ){
int a1 = 1 ,b1 =100,c1 =3, d1=4;
//a>b?
int max ;
if (a1>b1){
//a1>c1?
if(a1>c1){
if (a1>d1){
max = a1;
}
else{
max =d1;
}
}
//a1<=c1
else{
//c1>1d?
if (c1 >d1){
max = c1;
}
else {
max =d1;
}
}
}
//a1<=b1
else{
if (b1 >c1){
if (b1>d1){
max = b1;
}
else{
max =d1;
}
}
//b1<=c1
else{
if (c1>d1){
max = c1;
}
else{
max = d1;
}
}
}
System.out.println("max is" + max);
}
} */
//1
/* if (true){
执行语句;
}
//2：
if (){
执行语句;
}
else{
执行语句;
}
//3
if (){
执行语句;
}
else if (){
}
else{
执行语句;
}
*/
//_______________________________________________________________________________
//else if 定义字符串year来显示年龄区间
/* int age1 = 30;
String year = "";
if (age1 >=18 && age1 <=30){
year ="中年";
}
else if(age1 <18){
year ="少年";
}
else if(age1 >50 &&age1 <300){
year ="老年";
}
System.out.println(year);
*/
//_______________________________________________________________________________
/* switch(x){
case 1:
xxx
break;
case2 2：
}
//当x 的值为case1 输出某值
switch有四种表示类型：
1.byte
2.int
3.short
4.char */
/* int x =1;
switch(x){
case 1 :
System.out.println("x");
break ;
case 2 :
System.out.println("xx");
break ;
case 3 :
System.out.println("xxX");
break ;
default :
System.out.println("x?");
break ;
}
*/
//用switch写出四季 int byte char 都可以 当写成string，类型的时候要string ="3",那么case "3"
//345春，678夏，9 10 11秋季 mounth + 除以3
//if 和switch 的结合使用
/* int mounth =10;
int season = (mounth+1)/3 ;
if (mounth <1 || mounth >12){
System.out.println("月份输入错误");
}
else{
switch(season){
case 0 :
System.out.println("冬季");//1
break ;
case 1 :
System.out.println("春季");//234
break ;
case 2 :
System.out.println("夏季");//567
break ;
case 3 :
System.out.println("秋季");//8910
break ;
case 4 :
System.out.println("冬季");//11 12
break ;
}
} */
// ________________________________________________________________________________
//while 循环
/* while (exp){
...循环体
} */
/* int i = 1;
while(i <= 10){
System.out.println(i);
i ++ ;
} */
//打印1-100的和
/* int i = 1;
int sum = 0;
while(i <= 100){
sum = sum + i ;
i++;
}
System.out.println(sum);
}
}
*/
// ________________________________________________________________________________
//for 循环体 for（初始化表达式，循环表达式，循环后的操作表达式）
/* for (int i = 0; i <10 ; i++){
System.out.println(i);
}
*/
//练习题
/* float score = 78.800f;
String level = "";
if (score >=0 && score <=60){
level ="差";
}
else if(score >=60 && score <70){
level ="中";
}
else if(score >=70 && score <80){
level ="良";
}
else if(score >=80 && score <100){
level ="好";
}
else{
level ="非法值";
}
System.out.println(level);
}
}
*/
//求1-1000的质数
/* int j ;
for (int i = 2; i<=1000; i++){
boolean flag = false;
for( j=2; j<i/2; j++){
if (i%j == 0){
flag = true;
break;
}
}
if (flag==false){
System.out.println(i);
}
} */
//打印10行；定义n=10行，正三角打印
/* int n =10;
for (int i = 1 ;i<=n ; i++){
for (int j = 1 ;j<=i; j++){
System.out.print("*");
}
System.out.println();//换行
}
*/
//乘法表
/* int n =9;
for (int i = 1 ;i<=n ; i++){
for (int j = 1 ;j<=i; j++){
System.out.print(j + "*" +i+ "=" +(i*j) + " ");
}
System.out.println();//换行
}
*/
//倒三角乘法表
/* for (int i = 9;i>=1; i--){
for (int j = 1 ;j<=i; j++){
System.out.print(j + "*" +i+ "=" +(i*j) + " ");
}
System.out.println();//换行
}
*/
//输出空三角
/* int n =9;//最后一行的个数
//i从5开始倒着往上，行数
for (int i = n/2+1 ;i>=1 ; i--){
for (int j = 1 ;j<=n; j++){
//当i=4时，条件1和2成立，打印第四个和第六个。当等于三的时候，第三个和第七个成立。
if (j==i||j==n+1-i||i==1){
System.out.print(j);
}
else{
System.out.print(" ");
}
}
System.out.println();//换行
} */
//输出2的1-64次幂的和
/* BigInteger a = BigInteger.valueOf(2);
BigInteger sum = BigInteger.valueOf(0);
BigInteger a = BigInteger.valueOf(0);
for( int i = 1 ; i <= 64 ; i++){
a =a +sum;
sum = sum.add(a.pow(i));
System.out.println(a);
}
*/
//输出2的1-64次幂的和 每次的数乘以2
/* int i;
int a =1;
int sum =0;
for (i =0 ;i<65 ;i++){
sum = sum +a;
a = a*2;
}
System.out.println(sum);
*/
//百钱买百鸡
/* int i ,j,k;
for (i=0;i<=20;i++){
for (j=0;j<=33;j++){
for (k=0;k<=99;k=k+3){
if ((k+i+j ==100)&&(i*5+j*3 +k/3 ==100))
System.out.println("大"+i+"中"+j+"小"+k);
}
}
} */
//正常思路打印空三角
0000* 0
000*0* 1
00*000* 2
0*00000* 3
********* 4
int line =5;//循环的所有行
for (int i =0 ; i<line;i++){
//输出n个空格(0)
for(int j =0; j<line-1-i;j++){
System.out.print(" ");
}
System.out.print("*");//之后打印*
//后半部分处理最后一行
if (i ==(line -1)){
for(int j = 0; j<2*i;j++){
System.out.print("*");
}
}//中间行
if ( i !=0 && i!=(line-1)) {
//输出2n-1个空格
for(int j =0; j<2*i -1;j++){
System.out.print(" ");
}
System.out.print("*");
}
System.out.print("
");
}
}
}