what's a good way to read each line of a file into an array

I have a file with an unkown number of lines. Each line is going to be red into an array of structs. What is the best way for doing this? For example do I have to go through the entire file once, just to determine the number of lines so I can make the array that size?

No... Just use a std::vector and grow it as you go.

Assuming it's a pretty simple struct, this is the approach I would take...

Code:

---

ifstream input_stream ( "input_file.txt" );
string input = "";
vector <my_struct> input_objects;

while ( !input_stream.eof() )
{
        getline(input_stream, input);
       
        ...from here you can tokenize/parse the string "input"...
       
        input_objects.push_back( struct_you_created );
}

---

Some might take a different approach. I don't by any means call this the "right way" or the "only way".

Overload operator>> for your struct and insert into vector as mentioned above. If done properly, the whole file processing and vector storing loop can usually be reduced to a couple lines:

Code:

---

while( input_file >> temp_struct )
  struct_vector.push_back(temp_struct);

---

Quote:

---

Originally Posted by DavidP

Code:

---

while ( !input_stream.eof() )
{
        getline(input_stream, input);

---

---

Do I really need to say it? ;)

Ok thanks, got it.
If I want to take a field from a string and put it into a certain part of a struct, knowing the deliminator is a space, how would I do that?

For example if the line I'm reading has the format
"name callery id status" and I want to store the name in the section of the struct for it, etc.

So in PHP it would look something like this

PHP Code:

---

$array = explode(line, " ")
myStruct.name = $array[0]
myStruct.callery = $array[1]
myStruct.id = $array[2]
myStruct.status = $array3 


---

...just so my questions clear
in Java I'd use a scanner with space as the delimiter

Space is the default delimiter for >>.

can you remind me how that works?
for example if I know that the line starts with a number, and I wanted to read that into an int how would I do that?
currentLine >> callery;

oh, I figured it out, used a string stream