[PHP] IO operation in PHP!

<?php//The first way to read the file $file _path = "Db.ini";

        Determine if the file exists (must be judged) if (file_exists ($file _path)) {//Open file, specify file path, read mode $fp = fopen ($file _path, "A +");

        Read length $con = fread ($fp, FileSize ($file _path));

        The replacement character//php does not deal with special characters and needs to be converted $con = Str_replace ("\ n", "<br/>", $con);
    Echo $con;
    }else{echo "file does not exist";

    //close file, must fclose ($FP);
        The second way to read the file, automatically closes the file//direct access to the file content//To determine whether the file exists (must be judged) if (file_exists ($file _path)) {//directly get the contents of the file

        $con = file_get_contents ($file _path);

        Substitution character $con = str_replace ("\ n", "<br/>", $con);
    Echo $con;
    }else{echo "file does not exist";

        //I will close the file///Third way to read the file//while Circular read, suitable for large files//To determine whether the file exists (must be judged) if (file_exists ($file _path)) {
        Open File $fp = fopen ($file _path, "A +");
        $str = "";

        $buffer = 1024;
       While loop read, suitable for large file while (!feof ($fp)) {     $str = Fread ($fp, $buffer);
            $str = Str_replace ("\ n", "<br/>", $str);
        Echo $str;
    //close file, must fclose ($FP);
    }else{echo "file does not exist";

        The//fourth read file (automatically closes file) if (file_exists ($file _path)) {$arr = Parse_ini_file ("Db.ini");

        Print_r ($arr);
    mysql_connect ($arr [' Host '], $arr [' User '], $arr [' Password ']);
    }else{echo "file does not exist";
 }?> </body>