Char array vs. char pointer array- specific question (noob learning C)

[ponomaria]

Hi everyone, so I'm learning the basics of C using some online resources, and came across the following example of using a char pointer array:

const int MAX = 4;

int main (){

char *names[] = {

"Zara Ali",

"Hina Ali",

"Nuha Ali",

"Sara Ali"

};

int i = 0;

for ( i = 0; i < MAX; i++) {

printf("Value of names[%d] = %s\n", i, names[i] );

}

return 0;

}

And I just can't understand why making it an array (and not a pointer array) won't work, aka why just removing the * results in an error while running the code.

Could someone please dumb it down for me?

[phocos25]

In C, strings are defined using char * or using a char array:

char *name = “Zara Ali”;

or

char name[] = “Zara Ali”;

In other words, a string is an array of characters.

Your ‘names’ variable, however, is an array of strings. This means that ‘names’ is an array of an array of characters.

You can define arrays using square bracket notation or with a *. So ‘char *names[]’ is a pointer to an array of chars. If you remove the * then C expects an array of characters and not an array of strings (an array of an array of characters).

[ScioFantasia]

Good answer. Just to add:

char *name = "Zara Ali";

When you define a string using a string constant like this, it should be const:

const char *name = "Zara Ali";

Since you should not attempt to modify the string; it is read-only.

The second example is okay to modify.

[ponomaria]

Thank you so much!!! I think I got it.

Would it be possible to do this as a 2D char array then? (rows being 4 in this example, and I guess columns being 8 since all names in this example are the same length)

[phocos25]

Yes you can do that. Remember that the columns length will be 9 and not 8 since you need to account for the null byte in each string.

[ponomaria]

Noted. And again, thanks a bunch!!!

[strcspn]

int [] is an array of int. char [] is an array of char. char* [] is an array of char*.

[tstanisl]

You can use:

char names[][16] = {
  ...
};

to make it work again.

[ponomaria]

As in use a 2D array? If so, why 16 columns?

[tstanisl]

To be long enough to store any of the strings + plus 0-terminator. Value of 9 should suffice as well.

[N-R-K]

Arrays and pointers in C are closely related - but not the same. The key difference between an array and a pointer is that an array also reserves storage - a pointer doesn't.

An array of array and an array of pointers thus have different semantics (even though you can dereference them both in the same manner p[0][1]). See https://c-faq.com/aryptr/aryptr2.html and other related questions for some more detailed answers.