How to get pointer on array?

Question

I have such an array:

    const char arg_arr[][100] = {
        "a",
        "b",
        "c",
        "d",
    };

and then I have such a method ParseCmdLine(const char *argv[]);

So, in order to pass my arg_arr I need to get pointer to it.

I try to invoke this method such way ParseCmdLine(*arg_arr) or like this ParseCmdLine(&arg_arr), but it doesn't work.

Question is - how to pass this arr as a pointer?

The types const char arg_arr[][100] and const char *argv[] are incompatible. You can't convert the former to the latter; you need to rewrite the former. — Joseph Sible-Reinstate Monica
– Joseph Sible-Reinstate Monica, Commented Jul 13, 2020 at 14:06
const char arg_arr[][100] and const char *argv[] differ. char [][100] is an array of arrays of 100 chars. const char *argv[] is an array of pointers to const char. — KamilCuk
– KamilCuk, Commented Jul 13, 2020 at 14:06
@JosephSible-ReinstateMonica but how to do it? Or there is no way to pass these params? — Sirop4ik
– Sirop4ik, Commented Jul 13, 2020 at 14:10
@KamilCuk but how to do it? Or there is no way to pass these params? — Sirop4ik
– Sirop4ik, Commented Jul 13, 2020 at 14:11

Waqar · Accepted Answer · 2020-07-13 14:16:06Z

3

Change:

 const char arg_arr[][100] = {
 ...
};

To:

 const char *arg_arr[] = {
 ...
};

edited Jul 13, 2020 at 14:16

answered Jul 13, 2020 at 14:13

Waqar

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2 Comments

Waqar Over a year ago

Not forcing anything, just what was in the question. Copy pasta

chqrlie Over a year ago

@AlekseyTimoshchenko: note that ParseCmdLine must have a way to tell how many elements are present in the array. Either pass this count as an extra argument (argc) or add a trailing NULL pointer after the last string, or both as is done for the arguments of the main() function.

chqrlie · Accepted Answer · 2020-07-13 14:25:20Z

2

arg_arr is a constant array of arrays of char, which is a different type from what ParseCmdLine expects: a pointer to an array of pointers to constant char arrays.

You should define arg_arr this way:

const char *arg_arr[] = {
    "a",
    "b",
    "c",
    "d",
    NULL
};

and pass it directly as ParseCmdLine(arg_arr).

Note that ParseCmdLine must have a way to tell how many elements are present in the array. Either pass this count as an extra argument (argc) or add a trailing NULL pointer after the last string as shown above, or both as is done for the arguments of the main() function.

edited Jul 13, 2020 at 14:25

answered Jul 13, 2020 at 14:14

chqrlie

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Comments

user11381830 · Accepted Answer · 2020-07-13 14:49:27Z

0

How to get pointer on array?

Available options regarding what you have provided ( without changing your code ):

Numerically:

Alphabetically:

Here's a guide that I think might help.

answered Jul 13, 2020 at 14:49

user11381830

Comments

bogdyname · Accepted Answer · 2020-07-23 12:30:32Z

-3

The name of the array is essentially the address of its first element.

edited Jul 23, 2020 at 12:30

answered Jul 13, 2020 at 14:14

bogdyname

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