#include "base64.h"
int main()
{
std::ofstream fout;
bool is_binary = true;
fout.open("new.vtu", std::ios::binary);
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
if (is_binary)
{
fout << "\n";
double x[] = {56.25, 6.25, 0, 100, 6.25, 0, 56.25, 0, 0, 100, 0, 0};
int result_size;
char *encoding = base64((char *)x, sizeof(double) * 12, &result_size);
std::cout << result_size << std::endl;
fout.write(encoding, result_size);
free(encoding);
}
else
{
fout << "\n";
fout << "56.25 6.25 0\n";
fout << "100 6.25 0\n";
fout << "56.25 0 0\n";
fout << "100 0 0\n";
}
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "7.5 2.5 0\n";
fout << "10 2.5 0\n";
fout << "7.5 0 0\n";
fout << "10 0 0\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "0 2 1\n";
fout << "1 2 3\n";
fout << "\n";
fout << "\n";
fout << "3\n";
fout << "6\n";
fout << "\n";
fout << "\n";
fout << "5\n";
fout << "5\n";
fout << "5\n";
fout << "5\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout << "\n";
fout.close();
return 0;
}
```
if `is_binary = false`, the code can generate correct vtk file, but if `is_binary = true`, the code can not generate correct vtk file.
I already notice that the base64 encoding, the `base64.h` is copied from `https://github.com/superwills/NibbleAndAHalf/blob/master/NibbleAndAHalf/base64.h`
If I open the vtk file with `paraview`, it complains that:
```auto
Can not read point data array "solution" for PointData in piece 0. The data array in the element may be too short
```
the code is compiled with `g++ main.cpp`, and my machine is little endian.
I have already see many topic
- [https://stackoverflow.com/questions/10913666/error-writing-binary-vtk-files](https://stackoverflow.com/questions/10913666/error-writing-binary-vtk-files)
- [https://stackoverflow.com/questions/55829282/write-vtk-file-in-binary-format](https://stackoverflow.com/questions/55829282/write-vtk-file-in-binary-format)
- [https://stackoverflow.com/questions/10608217/how-to-write-ascii-and-binary-data-to-the-same-file-at-the-same-time](https://stackoverflow.com/questions/10608217/how-to-write-ascii-and-binary-data-to-the-same-file-at-the-same-time)
But I still can not figure out what I am doing wrong.
Can anyone help me? Thanks for your time.
---
### Author:  [@flaviu2](https://discourse.vtk.org/u/flaviu2)
#### Post date: [October 26, 2020, 8:58am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/2 "2020-10-26T08:58:35Z")
Just an idea, I would open a valid vtu file to see the differences. By the way, have you tried to read/save the same file with vtk library (vtkXMLUnstructuredGridReader)?
---
### Author:  [@qzxuhui](https://discourse.vtk.org/u/qzxuhui)
#### Post date: [October 26, 2020, 9:52am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/3 "2020-10-26T09:52:46Z")
Sir, I have zero experience in using vtk. I just have knowledge how to generate the vtk file.
---
### Author:  [@flaviu2](https://discourse.vtk.org/u/flaviu2)
#### Post date: [October 26, 2020, 10:33am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/4 "2020-10-26T10:33:04Z")
So, in your case I would find a valid vtu file and I inspect it and I would try to follow that rules. If you think this path is good, please tell me if you found a vtu file, if you didn’t found, I’ll try to find one for you.
P.S. No need to call me ‘sir’, I am just a simple man 🙂 .
---
### Author:  [@qzxuhui](https://discourse.vtk.org/u/qzxuhui)
#### Post date: [October 26, 2020, 10:37am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/5 "2020-10-26T10:37:12Z")
You are my teacher~ Great thanks bro. If you can find a simple vtu file with `ascii` and the corresponding version with `binary`, then I think I can handle the problem by myself.
---
### Author:  [@flaviu2](https://discourse.vtk.org/u/flaviu2)
#### Post date: [October 26, 2020, 10:40am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/6 "2020-10-26T10:40:20Z")
Is too much to say that I am on your teacher 🙂
I just try to help, if I can, that’s all.
You can find here few vtu files: [https://people.math.sc.edu/Burkardt/data/vtu/vtu.html](https://people.math.sc.edu/Burkardt/data/vtu/vtu.html)
---
### Author:  [@qzxuhui](https://discourse.vtk.org/u/qzxuhui)
#### Post date: [October 26, 2020, 10:49am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/7 "2020-10-26T10:49:20Z")
Thanks for your sharing. The sadness is that, your example is all ascii, I can not understand what is the difference between acsii and binary version of vtu file. 😭
---
### Author:  [@qzxuhui](https://discourse.vtk.org/u/qzxuhui)
#### Post date: [October 26, 2020, 12:13pm UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/8 "2020-10-26T12:13:44Z")
Sir, I obtain the file by myself. Unlucky, I still can not understand the relationship between ascii file and binary file. Could you please give me some advice on this topic? `https://discourse.vtk.org/t/how-to-convert-ascii-file-using-base64-encoding-to-binary-file/4489`
---
### Author:  [@cean\_wang](https://discourse.vtk.org/u/cean_wang)
#### Post date: [January 3, 2021, 10:42am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487/9 "2021-01-03T10:42:14Z")
Change this line:
`fout << "\n";`
to:
` fout << "\n";`
This post has a binary demo file. [Trying to write VTU files from fortran - Support - VTK](https://discourse.vtk.org/t/trying-to-write-vtu-files-from-fortran/470)