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copy contents of vector into file

开发者 https://www.devze.com 2023-04-12 20:56 出处:网络
i have following code for copyingcontent of vector into file #include<iterator> #include<algorithm>

i have following code for copying content of vector into file

#include<iterator>
#include<algorithm>
#include<fstream>
#include<iostream>
#include<vector>
using namespace std;

void dump(vector<int>& v){
    ofstream out1("C\\Users\\datuashvili\\Desktop\\vector.txt");

    if(!out1){
        exit(1);
    }
    copy(v.begin(),v.end(),ostream_iterator<int>(out1," "));
}
int main(){

    ofstream out1开发者_StackOverflow社区("C\\Users\\datuashvili\\Desktop\\vector.txt");
    vector<int>v;
    v.push_back(100);
    v.push_back(200);
    v.push_back(300);
    v.push_back(500);
    v.push_back(1000);
    dump(v);

    return 0;
}

but when i simple run this code,,there is not written into file which is created on desktop,why?could you tell me what is wrong with this code? EDITED: here is edited code which also does not work doesn't open files and also does not write,two version 1.version

#include<iterator>
#include<algorithm>
#include<fstream>
#include<ostream>
#include<iostream>
#include<vector>
using namespace std;
void dump( vector<int>& v){
    ofstream out1(("C:\\vector.txt"));

    if(!out1){
        exit(1);
    }

    copy(v.begin(),v.end(),ostream_iterator<int>(out1," "));
    out1.close();
}
int main(){

    vector<int>v;
    v.push_back(100);
    v.push_back(200);
    v.push_back(300);
    v.push_back(500);
    v.push_back(1000);
    dump(v);

    return 0;
}

2.

#include<iostream>
#include<fstream>
#include<ostream>   
#include<vector>
#include<algorithm>
#include<iterator>
using namespace std;
template<typename T>
void writeTo(const std::string& filepath,const  vector<T>& data)
{

 ofstream filestream("C:\\vector.txt");
 std::copy(data.begin(),data.end(),std::ostream_iterator<T>( filestream," "));
 filestream.close();

}
int main(){

   vector<int>test;
   test.push_back(1);
   writeTo<int>("C:\\vector.txt", test);

   return 0;
}


I suspect the problem is this:

ofstream out1("C\\Users\\datuashvili\\Desktop\\vector.txt");

should be;

ofstream out1("C:\\Users\\datuashvili\\Desktop\\vector.txt");
               ^^^^^

You could have found this out on your own by running under a debugger, observing the exit status of your program, or by adding print statements to your program.

In a debugger, you would have stepped through your code and discovered that you hit "exit(1)". Alternatively, you could have added something like cout << "Can't open file!\n"; to your if statement.


Try to start with a simpler, working version, then change things one by one: this example will just create the file in c:/

#include <fstream>
#include <vector>
using namespace std;

void dump( const vector<int> & v)
{
    ofstream out1("C:\\vector.txt");

    if(!out1)
    {
        exit(1);
    }
    copy(v.begin(),v.end(),ostream_iterator<int>(out1," "));
}

int main()
{
    vector<int>v;
    v.push_back(100);
    v.push_back(200);
    v.push_back(300);
    v.push_back(500);
    v.push_back(1000);
    dump(v);
    return 0;
}

As other people mentioned, your path is wrong (at least, missing the ":" in "c:\..."), and you should open the file in only one place.


Like Rob commented your path is still wrong. You missed the colon after the disk identifier. Your path needs to be something like this: "c:\...."

And you still open the stream twice which on the second try might fail since this resource is locked by the first call.

Try someting like this:

template< typename T >
void writeToFile( const std::string& filePath, const std::vector< T >& data )
{
  std::ofstream fileStream( filePath );
  std::copy(data.begin(), data.end(), std::ostream_iterator< T >(fileStream, " ") );

  fileStream.close();
}

int main()
{
  ...

  vector< int > test;
  test.push_back(1);

  writeToFile<int>( "c:\\test.txt", test );

  ...
}
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