C++ Comparing the length of two similar arrays

Question

I believe Array1 and Array2 are declared differently but they both do have the same type - char. Both Array1 and Array2 seem to contain the same exact values and the same amount of values. I don't understand why their length are different from each other. Can someone please explain why?

char Array1[ ] = { 1, 2, 3, 4, 5 };
char Array2[ ] = "\x01\x02\x03\x04\x05";

std::cout << "Length of Array1 = " << sizeof( Array1 )/sizeof( *Array1 )
          << std::endl
          << "Length of Array2 = " << sizeof( Array2 )/sizeof( *Array2 );

Output:

Length of Array1 = 5
Length of Array2 = 6

The second array is initialized with a string literal which contains an implicit `\0` at the end. — sgarizvi, Feb 27 '13 at 11:51
/Face-palm I can't believe I forgot about that! @sgar91 Well, that explains everything. — CLearner, Feb 27 '13 at 11:52
@PlasmaHH How it could be duplicate if he does not asks what is NT? =) — kassak, Feb 27 '13 at 11:53
I have flagged this post. The answer is because it was null terminated! It was simple as that. — CLearner, Feb 27 '13 at 11:54

hmjd · Accepted Answer · 2013-02-27T11:57:28.240

5

The second array has an extra character due to the implicit null terminating character present in the string literal.

From section 2.14.5 String literals of the C++11 standard (draft n3337) point 14 states:

After any necessary concatenation, in translation phase 7 (2.2), ’\0’ is appended to every string literal so that programs that scan a string can find its end.

edited Feb 27 '13 at 11:57

answered Feb 27 '13 at 11:52

hmjd

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Can't believe I've forgot about the null terminating character. Thanks. +1 – CLearner Feb 27 '13 at 11:56
I will accept this answer in 7 minutes. – CLearner Feb 27 '13 at 11:58

score 2 · Answer 2 · answered Feb 27 '13 at 11:51

2

Because strings a NULL-treminated. You have extra character at string literal '\0'

answered Feb 27 '13 at 11:51

kassak

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C++ Comparing the length of two similar arrays

2 Answers2