extract characters to '.'

Hello,

I am trying to write a function to extract a number of characters in a file name given to a function up to the '.' character.

My function is below. I am trying to copy the characters pointed to by the fName pointer to a data member dataSetName up to the '.' operator reached in the fName pointer.

Code:

void Layer::setDataSetName(char * fName)
{
	int result;	//result buffer

	//if it is a featureclass
	if(result = (strcmp(layerType, "featureclass") == 0))
	{
		int count = 0;	//holds count of characters in argument
		
		//count num of characters up to the '.' character
		for(int i = 0; fName[i] != '.'; i++)
		{	
			++count; 
		}

		cout << "count is " << count << endl;

		//allocate space for the dataSetName
		dataSetName = new char[count + 1];
		
		//copy the characters up the '.' character
		for(; *fName != '.'; fName++, dataSetName++)
		{ 
			*dataSetName = *fName;
			cout << "*dataSetName = " << *dataSetName << " *fName = " << *fName << endl;		
		}

		//place a null character after the last character
		*dataSetName = '\0';

	}	//end if a featureclass

	//else it is an image
	else
	{
		//keep the extension
		dataSetName = new char[strlen(fName) + 1];
		strcpy(dataSetName, fName);

	}	//end else it is an image
	
}	//end setDataSetName

For some reason I get no output for the dataSetName. Why is this not working?

Maybe try replacing (strcmp(layerType, "featureclass") == 0) with !(strcmp(layerType, "featureclass") == 0). I didn't look at the rest of your code, but .. err... whatever.

That part is ok. I should have mentioned the code will enter the if statement in this case.

> dataSetName = new char[count + 1];
It's pointing to the start of the allocated memory,

But by the time you do this
> *dataSetName = '\0';
It's pointing to the end of your allocated memory

Use strncpy to save all this messing about copying a char at a time

if(result = (strcmp(layerType, "featureclass") == 0))

this looks like an assignment which is a no no in conditional statements.

with strcpy you will copy the . into the new buffer, which he doesn't want to do. Therefore char by char copying is fine, it's actually what strcpy() does anyway. However, I would copy it using count and indexes for clarity sake.

Code:

for(int i = 0; i < count; i++)
  dataSetName[i] = fname[i];

dataSetName[i] = '\0';

Try using strtok to extract the filename.

Code:

#include <string.h>

...

char *p;
p = strtok(filename, ".");
cout << "filename : " << p << endl;
p = strtok(NULL, ".");
cout << "extension : " << p << endl;

...