Array of arrays of string correct declaration

Question

I need an array of arrays of string in my programm. I am declaring it so:

string edges[N][N] = {
{"0", "A", "0", "B", "E", "0", "0", "P1", "0"},
{"A", "0", "D", "I", "0", "0", "0", "0", "0"},
{"0", "D", "0", "0", "0", "H", "F", "0", "0"},
{"B", "I", "0", "0", "0", "H", "0", "0", "0"},
{"E", "0", "0", "0", "0", "0", "0", "P2", "0"},
{"0", "0", "H", "H", "0", "0", "0", "0", "P4"},
{"0", "0", "F", "0", "0", "0", "0", "0", "P3"},
{"0", "0", "0", "0", "0", "0", "0", "0", "0"},
{"0", "0", "0", "0", "0", "0", "0", "0", "0"},
};

Its okay, when I am trying to access strings with 1-letter value (A or B etc), but If I try to access string with 2-letters value, like edges[0, 7] (value is "P1"), programm will output 0. What's wrong?
It working fine if element is 1-letter like A, B, C, etc, but fail with P1 or P2.
Full programm listing and working programm is here http://ideone.com/ZMiVPE

"strings which are chars"? There is no such thing. Do you means strings that are only one character long (not counting the null terminator)? — ApproachingDarknessFish
– ApproachingDarknessFish, Commented Jan 17, 2014 at 1:22
Don't you mean edges[0][7]? edges[0, 7] is the same as edges[7]. — Angew is no longer proud of SO
– Angew is no longer proud of SO, Commented Jan 17, 2014 at 1:24
@Angew I meant edges[0][7]. Sorry. @ValekHalfHeart, sorry for my bad english, I eddited my question. — Sharikov Vladislav
– Sharikov Vladislav, Commented Jan 17, 2014 at 1:25
Your counting is off... remember that the first element in an array is [0], so edges[0][8] in an array of [9][9] is the last entry on the first line... "0". The same thing in your program on ideone... the indices you're printing are legitimately "0" elements in your array. See ideone.com/OywUMI — Tony Delroy
– Tony Delroy, Commented Jan 17, 2014 at 1:27
In your edited code, cout << " -(" << edges[next][prev] << ")-> " << names[tmp] << " : " << prev << " : " << next; <-- note you print prev before next, but you index in the opposite order. If you look up [next][prev] e.g. [8][5] you'll find they are "0". — Tony Delroy
– Tony Delroy, Commented Jan 17, 2014 at 1:37

Hao Luong · Accepted Answer · 2014-01-17 01:31:05Z

1

He Here's show value 0 in position [0,8], so, it's correct. well, it's correct. Array's going to arrange follow:

string edges[N][N] = {
{[0,0], [0,1], [0,2], [0,3], [0,4], [0,5], [0,6], [0,7], [0,8]},
  ....
[8,0], [8,1], [8,2], [8,3], [8,4], [8,5], [8,6], [8,7], [8,8]}}
};

answered Jan 17, 2014 at 1:31

Hao Luong

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Dan H · Accepted Answer · 2014-01-17 01:22:38Z

0

Because you want 7, not 8. C languages us a 0 index.

answered Jan 17, 2014 at 1:22

Dan H

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1 Comment

Sharikov Vladislav Over a year ago

Oops. Sure it is edges[0, 7], sorry. Edited.

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