please help!

This is a discussion on please help! within the C++ Programming forums, part of the General Programming Boards category; Hi, I just try to write a program in C++. I knew it is very easy. but I can't not ...

  1. #1
    Dongxu Xie
    Guest

    Unhappy please help!

    Hi,
    I just try to write a program in C++. I knew it is very easy. but I can't not figure out whai's wrong?
    I want to read a very long string in a .txt file, and then split this string into many substrings (the length of each substring is 50).
    My code like this:

    #include <fstream>
    #include<string>
    #include<cctype>
    #include <iomanip>
    using namespace std;
    int main()
    {
    string text;
    string s[100000];
    int i,j,n,L,ll;
    L=50;

    const char* filename="aa.txt";
    ifstream inFile(filename);
    if (!inFile)
    {
    cout<<endl<<"Failed to open file"<<filename;
    return 1;
    }
    inFile>>text;
    ll=text.length();
    n=ll/L;
    i=0;
    while (i<n)
    {
    j=i*L+1;
    s[i]=text.substr(j,L);
    i++;
    }
    }

  2. #2
    Registered User
    Join Date
    Apr 2003
    Posts
    2,662
    inFile>>text;

    That will only read in one word. The operator >> stops reading input when it encounters a whitespace, so n=ll/L may equal zero. What does your input file look like?

    j=i*L+1;

    If i=0, j=1 and you start the substring at position 1, but the string index starts at 0. Is that what you want? If text.length() is 5, the indexing goes from 0-4.
    Last edited by 7stud; 05-03-2003 at 09:08 PM.

  3. #3
    Pursuing knowledge confuted's Avatar
    Join Date
    Jun 2002
    Posts
    1,916
    Away.

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