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Markus Flohberger · Guest

i want to read from a file, that contains hex data like this:

3D72 EF99 3D72 EF99 3D72 EF99 3D72 EF99
....

i have added a short code example. if i compile it with gcc 2.96, i get
the correct data. however if i compile it with intels icpc 8.1 i get
confused data. (mostly zeros and wrong data values) it seems like the
intel compiler interprets the data values as wrong data types. (my
guess) then i used c code using fscanf() and it works with both compilers.

regards,
markus

code example:

#include <iostream>
#include <fstream>

using namespace std;

const int N = 1024;

int main()
{
short real[N];
short imag[N];

ifstream read_file("data.txt");

for(int row_count=0; row_count<N/4; row_count++)
{
for(int col_count=0; col_count<4; col_count++)
{
read_file >> hex >> real[4*row_count+col_count];
read_file >> hex >> imag[4*row_count+col_count];
}
}
read_file.close();
}

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wittempj@hotmail.com · Guest

when I add some checks to what I'm reading, like below I get an error
printed, as you make assumptions about the number of elements in your
file.
-#include <cstdlib>
-#include <iostream>
-#include <fstream>
-#include <vector>
-#include <sstream>
-#include <string>
-#include <stdexcept>

-using namespace std;

-const int N = 1024;

-class error : public runtime_error
-{
-public:
- error(const string& m):runtime_error(m) {};
- virtual const char* what() const throw() { return
std::runtime_error::what(); }
-};

-int main()
-{
- vector<int> real;
- vector<int> imag;

- stringstream errmsg;-

- ifstream read_file;
- read_file.open("c:\temp\data.txt", ios_base::in);
-
- real.reserve(N);
- imag.reserve(N);
-
- try
- {
- for(int row_count=0; row_count<N/4; row_count++)
- {
- for(int col_count=0; col_count<4; col_count++)
- {
- read_file >> hex >> real[4*row_count+col_count];
- if (read_file.fail())
- {
- errmsg.str("");
- errmsg << "error reading row " << row_count <<
" col " << col_count << -endl;
- throw error(errmsg.str().c_str());
- }
- if (read_file.eof()) break;
- cout << real[4*row_count+col_count] << "t";
- read_file >> hex >> imag[4*row_count+col_count];
- if (read_file.fail())
- {
- errmsg.str("");
- errmsg << "error reading row " << row_count <<
" col " << col_count << -endl;
- throw error(errmsg.str().c_str());
- }
- if (read_file.eof()) break;
- cout << imag[4*row_count+col_count] << "t";
- }
- }
- }
- catch (error& e)
- {
- cerr << e.what() << endl;
- }

- cout << "finished reading" << endl;
- for(int row_count=0; row_count - {
- for(int col_count=0; col_count - {
- cout << real[4*row_count+col_count];
- cout << imag[4*row_count+col_count];
- }
- cout << endl;

- }

- read_file.close();
- system("Pause");
- return EXIT_SUCCESS;
-}

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Teng Lin · Guest

It could be a standard c++ library problem.
I know there is a bug in libstdc++ 3.2 which will cause the same
problem. You
may need to check it first

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Ben Hutchings · Guest

Markus Flohberger wrote: