Search function using wildcard?

[andylbh]

Hi people, I just started C++ yesterday, I'm trying do some basic functions here, but I'm stuck.

Question 1:
I have a infile.txt

Product:Price:Quantity
: is the delimiter
e.g
Chocolate:10:30
Banana:5:15
Candy:2:50

I'm trying to search and delete a line.
Lets say I type Banana, it will delete the line Banana:5:15

It currently works only if I type the full line, Banana:5:15, but if I just type Banana, it will not delete.
Here's my progress so far.
It's a function.

void remove_product(string product)
{
	cout << "" << endl;
	ifstream myfile("infile.txt");
	ofstream tempfile("temp.txt");
	string line;	
	cout << "Delete Product: " << endl;
	cin >> product;
	while (getline(myfile,line))
	{
		if (line != product)
		{
			tempfile << line << "\n";
		}
	}
	myfile.close();
	tempfile.close();
	remove("infile.txt");
	rename("temp.txt","infile.txt");

}

Am I doing it wrongly from the start?
Is there a better way to do it?

Question 2:
How do I display a line that I want?

e.g
Chocolate:10:30
Banana:5:15
Candy:2:50

Which line do you want to display: 2

Banana:5:15

I can only display all lines in the file currenly.
Thanks in advance!

[ne555]

while (getline(myfile,line))
	if (line != product)

You need to write all the line because you are comparing all the line.

2_ What is your code for display? You need to discard all the lines till you find the one you are looking for

[kash kow ken]

for the second question, try using an if statement nested in a for loop. the invariant of the for loop must be the number of rows your on. When the number of rows(invariant) equals your selection... print that line.


h/o I will write some code... I have to look at the libraries to understand those types etc etc

[andylbh]

"You need to write all the line because you are comparing all the line."

So how do I delete the line by just entering the Product Name?
Or rather, I output something like:
1 Chocolate:10:30
2. Banana:5:15
3. Candy:2:50
Delete Line No.: 2
Then Banana will be deleted.
This is sort of like Question No.2 's function, but I don't understand how to do it.
My function will be not efficient if I have to type Banana:5:15 just to delete that line...

[ne555]

//Read till the first ':', ignore the rest of the line.
getline(myfile, line, ':');
myfile.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );
//Or read the entire line, but extract the interesting part.
getline(myfile, line);
if( product != line.substr(0, line.find(':')) )

[andylbh]

ne555, THANKS ALOT!!!

getline(myfile, line);
if( product != line.substr(0, line.find(':')) )

works like a charm.

Thanks !