threegrade.java

该JAVA源文件是求N個學生的成绩的最高分

import java.io.*;
import java.util.Scanner;
public class ThreeGrade {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int n;
		float MaxScore=0f,MinScore=0f,AvgScore=0f;
		Scanner scanner = new Scanner(System.in);
		System.out.println("please input n");
		n=scanner.nextInt();
    String[] name = new String[n];
    float[] score = new float[n];
	System.out.println("please input the name and grade of every student:");
    for(int i=0;i<n;i++)
    {  // student[i] = new String();
    	name[i] = scanner.next();
    	score[i] = scanner.nextFloat();
    }
    RandomAccessFile file1=null;
    RandomAccessFile file2=null;

    /**
     * write the name and grade into the file1
     */
    try {
    	file1 = new RandomAccessFile("f:\\1.dat","rw");
    	for(int i = 0;i<n;i++)
    	{
    		file1.writeUTF(name[i]);
    		file1.writeFloat(score[i]);
    		
    	}
		
	} catch (FileNotFoundException e) {
		// TODO: handle exception
		e.printStackTrace();
	}catch (IOException e1) {
		// TODO: handle exception
		e1.printStackTrace();
	}finally{
		if(file1 != null){
			try {
				file1.close();
			} catch (Exception e2) {
				// TODO: handle exception
				e2.printStackTrace();
			}
		}
		
	}
	try {
		file2=new RandomAccessFile("f:\\2.dat","rw");
    	file1 = new RandomAccessFile("f:\\1.dat","r");
		float[] score2 = new float[n];
		String[] name2 = new String[n];
		int i=0;
		name2[i] = file1.readUTF();
		score2[i]= file1.readFloat();
		MaxScore = MinScore = score2[i];
		AvgScore  = AvgScore+score2[i];
		for( i=1;i<n;i++){
			name2[i] = file1.readUTF();
			score2[i]= file1.readFloat();
			AvgScore  = AvgScore+score2[i];
			if(i!=1){
			if(score2[i]>MaxScore)MaxScore=score[i];
			if(score2[i]<MinScore)MinScore=score[i];
			
			}
		}
		System.out.println("the max score is "+MaxScore);
		System.out.println("the min score is "+MinScore);
		System.out.println("the avager score is "+AvgScore/n);

		file2.writeFloat(MaxScore);
		file2.writeFloat(MinScore);
		file2.writeFloat(AvgScore);
	} catch (FileNotFoundException e) {
		// TODO: handle exception
		e.printStackTrace();
	}catch (IOException e1) {
		// TODO: handle exception
		e1.printStackTrace();
	}finally{
		if(file2 != null){
			try {
				file2.close();
			} 
			catch (Exception e2) {
				// TODO: handle exception
				e2.printStackTrace();
			}
		}
		if(file1 != null){
			try {
				file1.close();
			} 
			catch (Exception e2) {
				// TODO: handle exception
				e2.printStackTrace();
			}
		}
	}
	}

}