How to read a word into a string ignoring a certain character.

Question

I am reading a text file which contains a word with a punctuation mark on it and I would like to read this word into a string without the punctuation marks.

For example, a word may be " Hello, "

I would like the string to get " Hello " (without the comma). How can I do that in C++ using ifstream libraries only. Can I use the ignore function to ignore the last character?

Thank you in advance.

Answer 1

Try ifstream::get(Ch* p, streamsize n, Ch term).

An example:

char buffer[64];
std::cin.get(buffer, 64, ',');
// will read up to 64 characters until a ',' is found
// For the string "Hello," it would stream in "Hello"

If you need to be more robust than simply a comma, you'll need to post-process the string. The steps might be:

1. Read the stream into a string
2. Use string::find_first_of() to help "chunk" the words
3. Return the word as appropriate.

If I've misunderstood your question, please feel free to elaborate!

Answer 2

If you only want to ignore , then you can use getline.

 const int MAX_LEN = 128;
 ifstream file("data.txt");
 char buffer[MAX_LEN];

 while(file.getline(buffer,MAX_LEN,','))
 {
  cout<<buffer;
 }

EDIT: This uses std::string and does away with MAX_LEN

ifstream file("data.txt");
string string_buffer;    
while(getline(file,string_buffer,','))
{
  cout<<string_buffer;
}

Answer 3

One way would be to use the Boost String Algorithms library. There are several "replace" functions that can be used to replace (or remove) specific characters or strings in strings.

You can also use the Boost Tokenizer library for splitting the string into words after you have removed the punctuation marks.