I have a char array with a fixed length of 2 and I want to read a 2 byte subsection of data from a buffer of size 1024 starting from index ‘0’.
char signature[2];
char arr[1024]; // this is populated with data
memcpy(&signature, &arr[0], sizeof this->signature);
If I manually look at the first two characters in arr with a for loop
for (int i = 0; i < 2; i++) {
std::cout << arr[i] << std::endl;
}
it outputs:
B
M
however when I read signature:
std::cout << signature << std::endl
std::cout << sizeof signature << std::endl;
it comes up with this:
BM�
3
I don’t understand what’s going on. My solution complies with all online examples of how to utilize memcpy.
build:
g++ -std=c++2a -I./include src/*.cpp -o res
I don’t understand what’s going on. My solution complies with all online examples of how to utilize memcpy.
>Solution :
The memcpy works but your code for displaying the result is incorrect.
Passing a char array to std::cout only works if the array contains a null-terminated string.
To display a char array that does not contain a null terminated string you could do something like:
for (char ch : signature)
std::cout << ch;
std::cout << '\n';