import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

 

public class JavaFile {

  public static void main(String[] args) {

   try {

   // read file content from file

   StringBuffer sb= new StringBuffer("");

   

   FileReader reader = new FileReader("c://test.txt");

   BufferedReader br = new BufferedReader(reader);

   

   String str = null;

   

   while((str = br.readLine()) != null) {

     sb.append(str+"/n");

     

     System.out.println(str);

   }

   

   br.close();

   reader.close();

   

   // write string to file

   FileWriter writer = new FileWriter("c://test2.txt");

   BufferedWriter bw = new BufferedWriter(writer);

   bw.write(sb.toString());

   

   bw.close();

   writer.close();

  }

  catch(FileNotFoundException e) {

     e.printStackTrace();

   }

   catch(IOException e) {

     e.printStackTrace();

   }

  }

 

}

#include<string>
#include<iostream>
#include<stdlib.h>
#include<fstream>
int main()
{
std::string file_name="123";
std::ifstream fin(file_name.c_str());
std::string textline[3];
for(int i=0;i<3;++i)
 getline(fin,textline[i],'\n');//遇到换行结束这一行的读取
for(int i=0;i<3;++i)
std::cout<<textline[i]<<'\n';

return 0;
}

 <?php 
  
 /** 
  * 按行读取文件 
  * @param string $filename 
  */ 
 function readFileByLine ($filename) 
 { 
  $fh = fopen($filename, 'r'); 
   
  while (! feof($fh)) { 
   $line = fgets($fh); 
   echo $line; 
  } 
   
  fclose($fh); 
 } 
  
 // test 
  
 $filename = "/home/wzy/test/sort.txt"; 
  
 readFileByLine($filename); 

 #include <stdio.h> 
 #include <stdlib.h> 
 #include <string.h> 
  
 #define LEN 1024 
  
 int main(void) 
 { 
  char filename[LEN], buf[LEN]; 
  FILE *fp; 
  int len; 
  
  scanf("%s", filename); 
  
  fp = fopen(filename, "r"); 
  
  if (fp == NULL) exit(-1); 
  
  while (fgets(buf, LEN, fp) != NULL) { 
   len = strlen(buf); 
   buf[len - 1] = '\0'; // 去掉换行符 
  
   printf("%s\n", buf); 
  } 
  
  return 0; 
 }