C++ How to choose file size as array size

I can't use file size as array size, because it should be a constant. But I made it constant.

ifstream getsize(dump, ios::ate);
const int fsize = getsize.tellg(); // gets file size in constant variable
getsize.close();

byte dumpArr[fsize] // not correct
array<byte, fsize> dumpArr // also not correct
byte *dumpArr = new byte[fsize]; // correct, but I can't use dynamic array

I need to create std::array with the file size.

Solution

You need a compile-time constant to declare arrays so you have two options:

Give up the idea to create an array and use a std::vector instead:

std::ifstream file("the_file");
std::vector<std::uint8_t> content(std::istreambuf_iterator<char>(file),
                                  std::istreambuf_iterator<char>{});

If the file you want to read isn't supposed to change after you've compiled the program, make the file a part of the build system. Example makefile:
```
program: source.cpp filesize.h
    g++ -o program source.cpp

filesize.h: the_file
    stat --printf '#pragma once\n#define FILESIZE %sULL\n' the_file > header.h
```
... and use FILESIZE inside source.cpp to declare your array.