Boost String Replace Doesn't Replace Newline With String

Question

I am creating a function for my libspellcheck spell checking library that checks the spelling of a file. It's function is to read a text file and send its contents to the spell checking function. In order to have the spellchecking function process the text correctly, all newlines must be replaced with a space. I decided to use boost for this. Here is my function:

spelling check_spelling_file(char *filename, char *dict,  string sepChar)
{

    string line;
    string fileContents = "";
    ifstream fileCheck (filename);
    if (fileCheck.is_open())
    {
        while (fileCheck.good())
            {
                getline (fileCheck,line);
            fileContents = fileContents + line;
        }

        fileCheck.close();
    }
    else
    {
        throw 1;
    }

    boost::replace_all(fileContents, "\r\n", " ");
    boost::replace_all(fileContents, "\n", " ");

    cout << fileContents;

    spelling s;
    s = check_spelling_string(dict, fileContents, sepChar);

    return s;
}

After compiling the library, I created a test application, with a sample file.

Test application code:

#include "spellcheck.h"

using namespace std;

int main(void)
{
    spelling s;
    s = check_spelling_file("test", "english.dict",  "\n");

    cout << "Misspelled words:" << endl << endl;
    cout << s.badList;
    cout << endl;

    return 0;
}

Test file:

This is a tst of the new featurs in this library.
I wonder, iz this spelled correcty.

The output is:

This is a tst of the new featurs in this library.I wonder, iz this spelled correcty.Misspelled words:

This
a
tst
featurs
libraryI
iz
correcty

As you can see, the newlines are not being replaced. What am I doing wrong?

score 5 · Answer 1 · answered Aug 02 '13 at 19:23

5

std::getline doesn't read newline characters when it extracts from the stream and so they're newer written in fileContents.

Also, you don't need to search and replace "\r\n", streams abstract this away and translate them to '\n'.

answered Aug 02 '13 at 19:23

jrok

51,107
8
99
136

score 4 · Accepted Answer · edited May 23 '17 at 11:50

std::getline() extracts the newline character from the stream but does not include it in the returned std::string, so there is no newline characters in fileContents to be replaced.

Also, check result of input operations immediately (see Why is iostream::eof inside a loop condition considered wrong?):

while (getline (fileCheck,line))
{
    fileContents += line;
}

Alternatively, to read the contents of the file into a std::string, see What is the best way to read an entire file into a std::string in C++? and then apply the boost::replace_all().

Boost String Replace Doesn't Replace Newline With String

2 Answers2