[英]reading and writing files into java
I have to create a file named Lab13.txt. 我必须创建一个名为Lab13.txt的文件。 In the file I have 10 numbers. 在文件中,我有10个数字。 I import the 10 numbers and have to Multiply all the numbers from Lab13.txt by 10 and save all the new numbers a new file named Lab13_scale.txt. 我导入了10个数字,必须将Lab13.txt中的所有数字乘以10,然后将所有新数字保存到名为Lab13_scale.txt的新文件中。 so if the number 10 is in lab13.txt it prints 100 to Lab13_scale.txt. 因此,如果数字13位于lab13.txt中,则它将100输出到Lab13_scale.txt。 Here is what I have: 这是我所拥有的:
import java.io.*;
import java.util.Scanner;
public class lab13 {
public static void main(String[] args) throws IOException{
File temp = new File("Lab13.txt");
Scanner file= new Scanner(temp);
PrintWriter writer = new PrintWriter("Lab13_scale.txt", "UTF-8");
writer.println("");
writer.close();
}
}
How do I multiply the numbers by 10 and export it to the new file? 如何将数字乘以10并将其导出到新文件?
This code is simple as this: 这段代码很简单:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;
public class Lab13 {
public static void main(String[] args) throws FileNotFoundException {
Scanner scan = new Scanner(new File("Lab13.txt"));
PrintWriter print = new PrintWriter(new File("Lab13_scale.txt"));
while(scan.hasNext()){
print.write(10 * scan.nextInt()+"\n");
}
print.close();
scan.close();
}
}
I'll give you a different approach. 我给你一个不同的方法。 I have wrote this from memory, let me know if you have any errors. 我是从内存中写的,如果有任何错误,请告诉我。 I assumed the numbers are one on each line. 我假设每行数字是一个。
public static void main(String[] args)
{
String toWrite = "";
try{
String line;
BufferedReader reader = new BufferedReader(new FileReader("Lab13.txt"));
while((line = reader.readLine())!=null){
int x = Integer.parseInt(line);
toWrite += (x*10) + "\n";
}
File output = new File("lab13_scale.txt");
if(!output.exists()) output.createNewFile();
FileWriter writer = new FileWriter(output.getAbsoluteFile());
BufferedWriter bWriter= new BufferedWriter(writer);
bWriter.write(toWrite);
bWriter.close();
}catch(Exception e){}
}
If the numbers are separated by spaces, use 如果数字用空格隔开,请使用
file.nextInt();
Full Code: 完整代码:
int[] nums = new int[10];
for(int i = 0; i < 10; i++){
nums[i] = file.nextInt();
nums[i] *= 10;
}
after writer.println("");
在writer.println("");
for(int i = 0; i < 10; i++){
writer.println(nums[i]);
}
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