write/read to file, but where?

[bluegreenisland]

Hi everyone,
I am new to this, so am bound to make blunders ~just let me know & I'll correct them.
I am hoping to learn how to write to a file, make changes to the data, and read.
I have a class definition in a .h file, the member functions definitions in a .cpp file, and a driver program which has two functions besides main(): writeFile() and readFile().
My problem is that I don't know what to do now! I tried declaring an object of my class in main() and using that object to pass a string called "a" to my file. Hmm. No go.
Can I have a clue, please?

int main()
{
AnagramCheck dataset1(3, "tan", 4, " ant");

writeFile();
readFile();

return 0;
}

void writeFile()
{
ofstream outFile("anagrams.dat", ios::out);//creates an ofstream object

if(!outFile)
{
cerr << "File could not be opened." << endl;
exit(1);
}

outFile << dataset1.geta();

outFile.close();
}

void readFile()
{
ifstream inFile("anagrams.dat", ios::in);//second argument (file mode) not necessary

if(!inFile)
{
cerr << "no" << endl;
exit(1);
}

while(inFile.peek() != EOF)
cout.put(inFile.get);

inFile.close();
}

[sicarie]

Depends on what you're trying to do. If you are trying to use the function to read a line from a file, you need to return that line (probably in a string, or pointer to a string), and if you are writing to the file, you need to pass the string (or pointer to character array) to the function.

But it also looks like you have that AnagramCheck, is that what you are trying to pass?

[bluegreenisland]

Hi Sicorie,
My instructions say that my program should accept two command line arguments: the first is the name of an input file and the second the output file. The input contains a number of data sets of 4 lines (int, string, int, string). Then I must generate an output file that for each data set does three processes (create new strings that convert the old to uppercase, determine how many words, and compare for "anagramness"). I pretty much have my functions, I think. I am to put the functions that manipulate the strings in a separate file, which is why I created a class. Was that wise? I wonder how to get the dataset into the file, and from where to call the functions. Does this make it clear? Here is my AnagramCheck.h file:


class AnagramCheck
{
private:
int aSize;
string a;
int bSize;
string b;

public:
AnagramCheck();//default constructor
AnagramCheck(int xSize, string x, int ySize, string y);
void setData(int xSize, string x, int ySize, string y);
int AnagramCheck::getaSize() const;
string AnagramCheck::geta() const;
int AnagramCheck::getbSize() const;
string AnagramCheck::getb() const;
int count_words(string c);
string make_upcase(string c);
int ckForChar(string a, string b);
bool are_anagrams(string a, string b);
};

Oh, and I hope you know how much you are appreciated!

[sicarie]

I'm not sure how necessary an entire class would be for a program this size - but it's definitely on the edge, if you decided to, then all the better to get experience with classes and good programming practices.

To accept command-line input, the 'int main()' needs something in the parentheses - 'int argc, char* argv[]' Then you can access the things in argv[] as you need them (the string,int,string,int) as an array.

It seems that, as you're sort of stuck on the execution of your program, I would go back to the "algorithm board". You would call the three functions from your main after reading them in and properly initializing the Anagram type, and then you would need some communication between the results of the three functions in the Anagram class (either returning, or directly calling - which might involve moving the printToFile() to your Anagram class). One of the tricks is to not make it more complicated than it needs to be.

so my pseudocode would be

get input from user
make sure it's proper type (char * coming in, and you said 2 would be ints...)
initialize anagram
set as uppercase
determine words
compare 'anagramness'
write to file

does that help clarify?

[bluegreenisland]

Exactly what I needed. What a relief. Thank you!