location certain line in a file to then write over

[maharris]

I'm trying to have the user enter the information, then entering the bookname to go to that point in the file so it can then be written over.

fstream reservationFile;												//creating output stream file to write reservation input

	reservationFile.open("reservationLog.txt");
	(ios::app);
	if(reservationFile.fail()){
		cout<<"File reservation unsuccessfully opened."<<endl
			<<"Please check to see if file exists."<<endl;
		exit(1);
	}
int main(){
int bookName;
int currentDate;
int startDate;
int lengthStay;
cout<<"Please enter book name:"<<endl;								//enter book name
				
				cin>>bookName;
				
				reservationFile<<bookName;									//write book name to reservationFile file
				
		
				cout<<endl<<"please enter toady's date(yyyymmdd):"<<endl;			//enter current date
				cin>>currentDate;	
				reservationFile<<currentDate;								//write current date to reservationfile
				cout<<endl<<"please enter start date:(yyyymmdd)"<<endl;				//enter start date
				cin>>startDate;
				reservationFile<<startDate;									//write start date to reservationfile
			 
				cout<<"Please enter length of stay:"<<endl;						//enter length of stay
				cin>>lengthStay;
				reservationFile<<lengthStay;							//write length of stay to reservation file


			
		
	
																		
			
				cout<<"Welcome to the edit booking menu!"<<endl
					<<"select booking"<<endl;
				cin>>bookName;
				cout<<reservationFile;
				
			
				}

[IceThatJaw]

I need to get to bed and take my last final in the morning but I noticed you are using an fstream so I take it that you want to both read and write through it.

I am not positive on this but I believe that it is automatically set to be an input filestream only so you might have to enable both by using:


reservationFile.open("reservationLog.txt", fstream::in | fstream::out);

[maharris]

bump

[IceThatJaw]

Show us the the file. Depending on how it is formatted it could be pretty simple in finding and overwriting the booknames.

[maharris]

its not updating to when i run it again, but

mike20111204201112161-858993460m-858993460-858993460-858993460

[maharris]

bump

[IceThatJaw]

Ok, so I took some time and browsed this site and I can show you 95% of the way. This code will find the bookname and overwrite it but it will only work perfectly if the number of characters are the same. So I guess it's up to you to figure out how to make it work for different sized booknames. You can do it guy, I have faith in you!

int main() {

	fstream fin;
	string tmp;
	string name = "Dave";
	string newName = "Joe";
	long pos;
	
	fin.open("reservationLog.txt", fstream::in | fstream::out); 

  	getline(fin, tmp, '-'); 
 
	while (fin) {
	        if (tmp == name) {
			pos = fin.tellp();
			fin.seekp (pos - name.length() - 1);
			fin << newName;			
		}
		getline(fin, tmp, '-'); 
	}
        
        return 0;
}