FStream Question

This is a discussion on FStream Question within the C++ Programming forums, part of the General Programming Boards category; After I create a random text file called text.txt with Code: std::fstream fin, fout; fout.open("c:\text.txt", std:ios::out); //ignore the smily its ...

  1. #1
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    FStream Question

    After I create a random text file called text.txt with
    Code:
    std::fstream fin, fout;
    fout.open("c:\text.txt", std:ios::out); //ignore the smily its an ':'':'o';
    if(!fout.is_open()) return 0;
    
    //I wrote 10 lines of strings to the file with:
    while (int i = 0; i <= 10; i++) {
    fout << "This is line #" << i++ << std::endl;
    fout.close();
    
    //now I open the file to get the string of characters for each line 
    //and print them to the screen
    fin.open("c:\text.txt", std::ios::in);
    if(!fin.is_open()) return 0;
    std::string str;
    while (!fin.eof()) {
    std::getline(fin, str, '\n'); //why is it FN? and '\n' for params???
    std::cout << str << std::endl; //prints str line.
    fin.close(); //close fstream.
    system ("PAUSE");
    }
    My question is, if I create a text file manually - and simply want to get the lines of strings in the file how do I go about this? Simply use fin.open("c:\text.txt", std::ios::in);? and then instantiate a string to retrieve all data untill the end of the file? ::

    ::EDIT:: - also why do I need to use standard before each operator? i.e. std::cout, std::string str?

  2. #2
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    Re: FStream Question

    The whole file content in one string?
    Code:
    #include <fstream>
    #include <string>
    #include <sstream>
    
    using namespace std;
    
    int main()
    {
    	ifstream file("test.txt");
    
    	stringstream stream;
    	stream << file.rdbuf();
    
    	string fileContent = stream.str();
    }
    Originally posted by CPP-Null i
    ::EDIT:: - also why do I need to use standard before each operator? i.e. std::cout, std::string str? [/B]
    No,try using namespace std; or using std::cout ,etc.

  3. #3
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    Where can I learn more about this topic? - Exspecially on the StringStream class? - also is it possible to divide the contents up in a file and store it at different variables? Like say I declare a = 5 in a text file. I read it in, and do c = a + 1. Will that yeild six?

    what does file.rdbuf() do?
    Last edited by CPP-Null; 05-25-2003 at 01:44 PM.

  4. #4
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    Im running into a problem - its not printing the string filecontent. =( - I tried cout << filecontent; didn't seem to print.

    Code:
    using namespace std;
    int main(){
    ifstream file1("c:\test.txt");
    stringstream stream;
    stream << file1.rdbuf();
    string filecontent = stream.str();
    getline(file1, filecontent, '\n');
    cout << filecontent;
    system("PAUSE");
    file1.close();
    }
    Last edited by CPP-Null; 05-25-2003 at 02:00 PM.

  5. #5
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    Take the getline out.After rdbuf the filepointer sits at end of file.You already had the whole content in the string,dont override it again.

  6. #6
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    I removed getline(), but the text being stored in the string thats read from the buffer isn't being printed to the string. All I get is the System ("PAUSE") message, not the text stored in the text file.

    Code:
    #include <iostream>
    #include <fstream>
    #include <string>
    #include <sstream>
    #include <stdlib.h>
    using namespace std;
    int main(){
    ifstream file1("c:\test.txt");
    stringstream stream;
    stream << file1.rdbuf();
    string filecontent = stream.str();
    cout << filecontent; //isn't this needed to print the filecontents?
    system("PAUSE");
    file1.close();
    }
    Preservation lies in thought, if all is forgotten who is to preserve?

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