How to use path in a buffer as file path in fprintf

void Log ::CreateLogFile1()
{
	char    szDate[12];
	char buf[150];
	int i=0;
	int iLevel;
 
	//get the path of ini file
	//	TO DO
	//check status of ini file
	//	TO DO
	//read ini file and get log directory path
	//	TO DO
	//create log file
	_strdate( szDate );
	//logfilename format ServerManagermm-dd--yy
	strcpy(buf,szLogDir1);
	strcat(buf, "\\");
	strcat(buf, "\\");
	strcat(buf,a);
		
	strcat(buf,szDate);
	strcat(buf,".txt");
 
	while(buf[i] != '\0')	// mm/dd/yy to mm-dd-yy conversion
	{
		if(buf[i] == '/')
			buf[i] = '-';
		i++;
	}
 
	ofstream pOS(buf,ios::app);
	pOS<<"\nBinary Strarted..\n"<<endl;
	pOS.close();
 
}

void Log ::WriteBinary(char bufg[139])
{
	char    szDate[12];
		char    szTime[12];
		char buf[2000];
		char bufpath[2000];
		int i=0;
		_strdate( szDate );
		_strtime( szTime );

		strcpy(buf,szLogDir1);
		strcat(buf, "\\");
		strcat(buf, "\\");
		strcat(buf,a);
		strcat(buf,szDate);
		strcat(buf,".txt");//as buf contain my file path and i want to use it as FILE*
			memcpy(bufpath,buf,sizeof(buf));
		while(buf[i] != '\0')
		{
			if(buf[i] == '/')
				buf[i] = '-';
			i++;
		}
		ofstream pOS(buf,ios::app);
		
		fprintf((FILE*)bufpath, "%s::%s::DATA IS::", szDate, szTime); 
		fwrite(bufg, 1, 138, (FILE*)bufpath);
		fprintf((FILE*)bufpath, "\n");

		
		
		pOS<<buf<< endl;
		pOS.close();


}

fprintf((FILE*)bufpath, "%s::%s::DATA IS::", szDate, szTime);