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carrayschar
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Reputation: 553

Char array assignment to another char array

I want to assign one char array to another, but the following does not work.

 unsigned char myval1[6] = {0x01, 0x01, 0x01, 0x01, 0x01, 0x01};
 unsigned char myval2[6];
 myval2 = &myval1[0];

Upvotes: 0

Views: 308

Answers (7)

Alex
Alex

Reputation: 10126

In C you an not assign the array. You should use memcpy() function to copy array.

memcpy(myval2, myval1, sizeof(myval2));

Upvotes: 1

Sks Sapare
Sks Sapare

Reputation: 37

try this

unsigned int myval1[6] = {0x01, 0x01, 0x01, 0x01, 0x01, 0x01};
unsigned int myval2[6];
unsigned int* add = &myval1[0];

cout << *add << endl;

Upvotes: 0

M.M
M.M

Reputation: 141544

A good idiom for this is:

memcpy(&myval2, &myval1, sizeof myval2);

By pairing &x and sizeof x you ensure that you always copy the right number of bytes, even if you make a mistake elsewhere with variable names.

The version suggested in the other posts works anyway because myval2 is an array, so (void *)myval2 == (void *)&myval2.

Upvotes: 0

unwind
unwind

Reputation: 399743

No, you cannot assign arrays in C.

You must manually copy each array element. The standard library function to do this is memcpy():

memcpy(myval2, myval1, sizeof myval2);

The final argument is the number of bytes to copy, and using sizeof is very much recommended. Note that if myval1 is smaller than myval2, the above will be undefined behavior since it will read beyond the bounds of myval1. You must be careful.

Upvotes: 0

Jarod42
Jarod42

Reputation: 217085

C-Array are not copy-assignable.
You have to do the copy yourself (using std::copy (C++) or memcpy (C)).
In C++11, you may use std::array instead.

Upvotes: 2

laune
laune

Reputation: 31290

This is one thing you cannot do with an assignment. One possibility is

memcpy( myval2, myval1, sizeof(myval2) );

Upvotes: 1

51k
51k

Reputation: 1443

You might try something like this..

unsigned char myval1[6] = {0x01, 0x01, 0x01, 0x01, 0x01, 0x01};
 unsigned char *myval2;
 myval2 = &myval1[0];

Upvotes: 0

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