Error in getline() Argument

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July 31st, 2009, 05:54 PM

nathanpc

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Error in getline() Argument

Hello,
When i try to compile this simple example for learning i have some errors while compiling:

Code:

#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
using namespace std;
int main()
{
    char temp[100];
    ifstream file("test.txt");
    string linha = getline(temp, 100, file);
    if(linha == "teste")
      {
         cout << "Hello, World";
      }
}

And here is the log of g++:

Code:

ubuntu@ubuntu-laptop:~/Desktop$ g++ -o test test.cpp
test.cpp: In function ‘int main()’:
test.cpp:10: error: cannot convert ‘char*’ to ‘char**’ for argument ‘1’ to ‘__ssize_t getline(char**, size_t*, FILE*)’
ubuntu@ubuntu-laptop:~/Desktop$

What is wrong?

Thanks,
Nathan Paulino Campos

July 31st, 2009, 06:03 PM

Scorpions4ever

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Your problem is around where you're using getline(). You should never have to use a char buf, when you have C++ and a string object.

Simply do this instead.

Code:

#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
using namespace std;
int main()
{
    ifstream file("test.txt");
    string linha;
    getline(file, linha);
    if(linha == "teste")
      {
         cout << "Hello, World";
      }
    return 0;
}

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July 31st, 2009, 06:24 PM

nathanpc

PixHost.tk Developer

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Thanks very much!!!!!!!!!!!!!

July 31st, 2009, 06:31 PM

nathanpc

PixHost.tk Developer

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But how i can do if my file is like this:

Code:

teste
hello

And i want to show the two, the one like in your post and the second like this:

Code:

    if(linha == "arquivo")
      {
         cout << "Testing...\n";
      }

How i can do this??????????

Last edited by nathanpc : July 31st, 2009 at 06:34 PM. Reason: put the code

July 31st, 2009, 07:18 PM

sizablegrin

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If you want to get two lines I suppose you could use "getline" twice. Stuff like that.

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July 31st, 2009, 07:24 PM

nathanpc

PixHost.tk Developer

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Location: Brazil

Posts: 58

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Thanks, but i solved thid problem: http://www.dreamincode.net/forums/showtopic117882.htm

Comments on this post

sizablegrin disagrees: Great. Nothing like making us waste and duplicate effort without telling us.

holodoc agrees: Balance... You found help elsewhere and even gave the link to the solution... Its unfair to derep
you for that.

Error in getline() Argument

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