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package
com.stella;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/** * 获取用户输入的数
* @author Administrator
*
*/
public
class GetUserInput {
private
static String str;
/**
* 获取用户输入
*/
private
static void getUserInput(){
BufferedReader rb = new
BufferedReader( new
InputStreamReader(System.in));
try
{
str = rb.readLine();
} catch
(IOException e) {
e.printStackTrace();
throw
new RuntimeException( "io异常!" );
}
}
/**
* 将用户输入的字符串类型转换为Integer类型
* @return
*/
public
static Integer getInt(){
getUserInput();
if (str == null
|| str.trim().equals( "" )){
throw
new RuntimeException( "用户输入不能为空!" );
}
try {
return
Integer.valueOf(str);
} catch (NumberFormatException e){
throw
new NumberFormatException( "您输入的类型有误!" );
}
}
} |
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package
com.stella;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public
static void main(String[] args) {
while ( true ){
System.out.println( "请输入一个整数" );
int
num = GetUserInput.getInt();
boolean
a = judge(num);
if (a){
System.out.println( "这个数是2的阶乘" );
} else {
System.out.println( "这个数不是2的阶乘" );
}
}
}
/**
* 获得用户输入的一个整数,然后计算它的平方和立方
*/
public
static void value(){
BufferedReader br = new
BufferedReader( new
InputStreamReader(System.in));
try
{
String str = br.readLine();
if (str != null
&& !str.equals( "" )){
int
v = Integer.valueOf(str);
print(v);
}
} catch
(NumberFormatException e) {
e.printStackTrace();
} catch
(IOException e) {
e.printStackTrace();
} finally {
try
{
br.close();
} catch
(IOException e) {
e.printStackTrace();
}
}
}
/**
* 求一个数的平方和立方
* @param is
*/
public
static void print( int
is){
System.out.println(is + "的平方值和立方值:" );
System.out.println( "平方值:"
+ is*is);
System.out.println( "立方值:"
+ is*is*is);
}
/**
* 判断一个数是不是2的阶乘
* 原理是:如果一个书是2的阶乘,则这个数减1和它自己进行“&”位运算结果为0
* @param x
* @return
*/
public
static boolean judge(Integer x){
if ((x & (x - 1 )) == 0
&& x != null ){
return
true ;
}
return
false ;
}
} |