java输入输出方式

oj

public class Main{
    public static void main(String[] args) {
    //主代码
    }
}
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Scanner读入

import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		int n=in.nextInt(); //读不到空格
		String str = in.nextLine();//读到回车结束
		float f = in.nextFloat();
		double d=in.nextDouble();
	}
}
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读取速度慢
读入未知数目键盘输入：

Scanner in =new Scanner(System.in);
String str;
while(true){
      if((str=in.nextLine()).equals(""))break;
}
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BufferedReader读入

import java.io.*;
public class Main{
    public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		try {  
		     String sn = br.readLine();  
		     int n=Integer.parseInt(sn);
		     String s=br.readLine();
		     String arr[]=s.split(" ");
		     double a[]=new double[n];
		     for(int i=0;i<n;i++){
		          a[i]=Double.parseDouble(arr[i]);
		      }
		      StringBuffer buffer = new StringBuffer();   
              buffer.append(s);
		 } catch (IOException e) {  
		    e.printStackTrace();  
		}
	}
}
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读取字符串，可以转换为其他类型

输出

System.out.println("yes");
System.out.printf("%.2f",res);
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