Why we use reinterpret_cast, while reading from file in c++

Answer 1

There is no need to: binary files have no restrictions on what you can read/write:

#include <fstream>
#include <string>
using namespace std::literals;
int main(){
std::ofstream("terca.bin", std::ios::binary) << "\0\x1a\xff"s << 5.14;
}
Where you’re likely to be using reinterpret_cast is when you’re writing the object representation - the actual bytes of RAM used to represent an object in your program. For example, if you want to dump the double with value 5.14 as the 8 bytes it’s made of in memory, and not as the four bytes of its decimal text representation (like I did in the first example):

#include <fstream>
int main(){
double d = 5.14; std::ofstream("terca.bin", std::ios::binary).write( reinterpret_cast<char*>(&d), sizeof d);
}
This reinterpretation isn’t really about file I/O, it’s about obtaining the underlying bytes of an object.

Answer 2

Because that's the only way to receive binary input from a file.

Answer 3

Xander Lim reinterpret_cast<dest_ptr_t>(src_ptr) changes the type of src_ptr to dest_ptr_t without changing anything in the underlying data. In most cases, it's unsafe and you shouldn't use it.

Answer 4

Because this actually is a reinterpret_cast, but hidden. Look here for more information: https://www.google.com/amp/s/embeddedartistry.com/blog/2017/2/28/c-casting-or-oh-no-we-broke-malloc%3fformat=amp

Answer 5

Xander Lim Sometimes you need it, though.

Answer 6

Raj kumar patel Please create a new thread. It will keep this thread on topic and it also helps yourself: More competent people will see the question.

Answer 7

no its working correctly without using reinterpret_cast

Answer 8

Binary input? Ok, how?

Answer 9

this way.

while(fileHandler.read((char*)&obj, sizeof(obj))
{
obj.showData();
}

Answer 10

Mohit the coder (M.S.D) Ok, I was unclear, but that's what I meant.

Answer 11

sachin singh Tell you what?

Answer 12

Hi

Answer 13

OK. I thought u say I don't need it. now I understand sometimes I still need it.

Answer 14

My xampp server is not working properly what can I do to fix it

Answer 15

what is this?

Answer 16

OK I won't use it.

Answer 17

Sometimes we need it