fstream help in Console C++
Author
I am reading from a text file which containts integers AND strings which are all mixed up. I need to sort all the stuff into an array of ints and an array of string. I am using fstream.h. So, i have a loop like:
while (!file.eof())
{
// Here is where i want to read stuff in
}
But i need a way of distinguishing whether what i am about to read in is of type int or string. Can ne1 help? All i can think of is reading it as a string then testing the ascii value of the first letter of that string to c whether its a number and using the atoi function to convert it to an int, and dump it in the array of ints or if it is not a number dump it in an array of strings. The obvious draw back to this method is what if one of my strings is like, "101Dalmations" and its just a stupid method. Again, ne ideas will be greatly aprreciated!
If its a file that is written by you, you should design your files and not make them messy.
If youre reading a file that can be anything, I dont know
If youre reading a file that can be anything, I dont know
Author
The file is NOT written by me. Its an assignment in my AP Computer Science class and our teacher said that we cannot re write the file. If i could have i would have.
Author
The file is NOT written by me. Its an assignment in my AP Computer Science class and our teacher said that we cannot re write the file. If i could have i would have.
uhm... There was a function IS_CHAR() or IS_INT() or something, I DONT KNOW FOR SURE! but I thought there was one
What you are talking about is a parser. May find some stuff about it on the web.
Off the top of my head something like this would do the trick:
I realise I just did ya homework but hey I''m feeling generous and not particularly pedagogical.
P.S. I think the way i think the way I converted from a string to an int was somewhat lame, anyone know a better way?
Off the top of my head something like this would do the trick:
#include <iostream>#include <sstream>#include <fstream>#include <vector>using namespace std;main(){ string ThisItem; vector<int> IntArray; vector<std::string> StringArray; ifstream File("test.txt"); if( File.fail() ) { cout << "Could not open file" << endl; return; } while( !File.eof() ) { File >> ThisItem; if( ThisItem.find_first_not_of("0123456789") != string::npos ) { // ThisItem contains non-numeric characters so treat as a string StringArray.push_back(ThisItem); } else { // all characters are numeric so treat as an int stringstream ss; int Temp; ss << ThisItem; ss >> Temp; IntArray.push_back(Temp); } } // verify cout << "Strings:" << endl; for( vector<string>::size_type i = 0; i < StringArray.size(); ++i) { cout << StringArray[i] << endl; } cout << "Ints:" << endl; for( vector<int>::size_type i = 0; i < IntArray.size(); ++i) { cout << IntArray[i] << endl; }} I realise I just did ya homework but hey I''m feeling generous and not particularly pedagogical.
P.S. I think the way i think the way I converted from a string to an int was somewhat lame, anyone know a better way?
You could read it as a string first, and then try to convert it to an int.
//... std::string str; the_ifstream >> str; int number=convert_to_number(str); if (conversion_succeeded) { do_something(number); } else { do_something(str); }//...
Author
Thanks a lot guys! MAD NICE. Both ways are good and i realize that you did my hwk for me, thanks a lot! But at least i learnt how to do it, not jsut blatant copying, (sort of)
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