Iterate over pointer to an array of char pointers

Question

Lets say I have the following code:

char *array[] = {"one", "two", "three"};
char *(*arrayPtr)[] = &array;

How do I iterate over array? I've tried doing this but doesn't work:

for(int i = 0; i < sizeof(array)/sizeof(array[0]); i++) {
    printf("%s\n", (*arrayPtr + i));
}

@StoryTeller I have to pass the variable array as to pointer to a struct — ssd20072
– ssd20072, Commented Apr 4, 2017 at 5:27
First things first, if you think you need to take an array address as in &array, you are probably wrong. — n. m. could be an AI
– n. m. could be an AI, Commented Apr 4, 2017 at 6:12
Pointers to arrays are rarely needed, mainly when they are elements of larger arrays (e.g with 2d arrays). In most cases a pointer to the first element of an array is more convenient and less confusing. — n. m. could be an AI
– n. m. could be an AI, Commented Apr 4, 2017 at 15:17

Community · Accepted Answer · 2017-05-23 12:17:31Z

2

The scheme you have is missing a derference. *arrayPtr + i is the address of the i-th element of the array. Meaning it's a char**. You need to at least dereference that:

printf("%s\n", *(*arrayPtr + i));

However, that isn't valid C you have there, since you omitted the array size when defining the pointer. I hope it's not the actual code you wrote.

Also, note that you can use the subscript operator as Blagovest Buyukliev pointed out, but be weary of operator precedence. It's (*arrayPtr)[i] and not *arrayPtr[i].

edited May 23, 2017 at 12:17

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answered Apr 4, 2017 at 5:27

StoryTeller - Unslander Monica

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6 Comments

Blagovest Buyukliev Over a year ago

Alternatively, (*arrayPtr)[i].

ssd20072 Over a year ago

Thanks a lot!! :)

ssd20072 Over a year ago

Do you mean the array size when defining 'array' or 'arrayPtr'?

StoryTeller - Unslander Monica Over a year ago

@SanketDeshpande - arrayPtr. It's a must have there. The size for array is deduced from the initializer, so no problem there.

StoryTeller - Unslander Monica Over a year ago

@SanketDeshpande - That's a possibility yes. But personally, a plain char** that's passed with a size parameter seems less verbose.

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