passing object to function, columns class Post: 302513284

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Top Forums Programming passing object to function, columns class Post 302513284 by LMHmedchem on Tuesday 12th of April 2011 07:00:21 PM

04-12-2011

Registered User

I have made some progress, I will deal with the issue of using string or stringstream in a little bit. Can a string be parsed by a delimiter using the same method I was using for stringstream, or do I have to do something different?

I have the function creating the objects,

Code:

// creates a data object and meta data object for each column
int createColObjs( stringstream &colsRowStream ){
   std::string rowCell;
   // parse header row into cells, tab delimiter
   while(getline(colsRowStream,rowCell,'\t')) {
      // create new column data object
      col_metadata newColMeta;  metadata.push_back(newColMeta);
      // create new column data object
      column_data newCol;  columns.push_back(newCol);
   }
   // clear the buffer
   colsRowStream.clear();
}

This is called with,
colsRowStream << storeSplitsRows[0];
createColObjs ( colsRowStream );

which dumps the first row into the stream and passes it to the create object function. I get a col metadata object and a col data object for each col in the input file. The objects are stored in vectors, metadata and columns respectively.

I am a bit stuck on the loading function, which parses the stream and loads it to the appropriate var in the col object.

Code:

// accepts a stringstream and parses the data in to columns
int metadata_row_toCol( stringstream &colsRowStream, 
                        std::vector<col_metadata>& metadata ){
   int i = 0;
   std::string rowCell;
   // parse row into cells, tab delimiter
   while(getline(colsRowStream,rowCell,'\t')) {
      metadata[i].content = rowCell;
      i++;
   }
   // clear the buffer
   colsRowStream.clear();
}

This above works, but is hard coded to put the data into metadata[i].content. I can't seem to see how I indicate that the first rows goes into content, but the next row goes into a different member. It seems like I should be passing a pointer to metadata[i].content, and not to the metadata vector of objects.If I did that, I could pass a pointer to metadata[i].type for the next row, etc. All the function would need to know is that it is expecting a pointer to a class variable. At any rate, I need to be able to tell the loading function where to put the data that is parsed out of the stream, but I can't seem to work out the syntax.

LMHmedchem

Last edited by LMHmedchem; 04-12-2011 at 08:13 PM..

LMHmedchem

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LEARN ABOUT PHP

fbsql_fetch_field

FBSQL_FETCH_FIELD(3)							 1						      FBSQL_FETCH_FIELD(3)

fbsql_fetch_field - Get column information from a result and return as an object

SYNOPSIS

       object fbsql_fetch_field (resource  $result, [int  $field_offset])

DESCRIPTION

	Used in order to obtain information about fields in a certain query result.

PARAMETERS

	      o $
		result -A result identifier returned by fbsql_query(3) or fbsql_db_query(3).

	      o $field_offset
		-  The	numerical  offset of the field. The field index starts at 0. If not specified, the next field that wasn't yet retrieved by
		fbsql_fetch_field(3) is retrieved.

RETURN VALUES

	Returns an object containing field information, or FALSE on errors.

	The properties of the object are:

	      o name - column name

	      o table - name of the table the column belongs to

	      o max_length - maximum length of the column

	      o not_null - 1 if the column cannot be
		NULL

	      o type - the type of the column

EXAMPLES

       Example #1

	      fbsql_fetch_field(3) example

	      <?php
	      fbsql_connect($host, $user, $password)
		  or die("Could not connect");
	      $result = fbsql_db_query("database", "select * from table")
		  or die("Query failed");
	      # get column metadata
	      $i = 0;
	      while ($i < fbsql_num_fields($result)) {
		  echo "Information for column $i:<br />
";
		  $meta = fbsql_fetch_field($result);
		  if (!$meta) {
		      echo "No information available<br />
";
		  }
		  echo "<pre>
	      max_length:   $meta->max_length
	      name:	    $meta->name
	      not_null:     $meta->not_null
	      table:	    $meta->table
	      type:	    $meta->type
	      </pre>";
		  $i++;
	      }
	      fbsql_free_result($result);
	      ?>

SEE ALSO

       fbsql_field_seek(3).

PHP Documentation Group 												      FBSQL_FETCH_FIELD(3)

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