How can I assign to new values to static array in C?

Question

Please advise me on how best to redeclare the array fields with new values using memcpy. If there's a better/optimum way to redeclare, please let me know that as well.

Here's my sample code:

#include <stdio.h> #include <string.h> #define array_size(array) sizeof(array)/sizeof(array[0]) struct user_profile { const char *first_name; const char *second_name; unsigned int age; }; int main() { struct user_profile fields[] = { {"david", "hart", 32}, {"billy", "cohen", 24}, }; for (int i = 0; i < array_size(fields); ++i) { printf("%s %s\n", fields[i].first_name, fields[i].second_name); } memcpy(fields, {{"zach", "roberts", 59}, {"mike", "fisher", 19}}, sizeof(fields)); return 0; }

Your call of memcpy shall not compile in C because this record {{"zach", "roberts", 59}, {"mike", "fisher", 19}} is not an expression. — Vlad from Moscow
– Vlad from Moscow, Commented Jan 9, 2023 at 11:04
Could you please share how best to use memcpy in this scenario? — kelsonic
– kelsonic, Commented Jan 9, 2023 at 11:07
OT: It doesn't matter much but.... The title says "static array" but there isn't any static array in the code — 4386427
– 4386427, Commented Jan 9, 2023 at 11:23
I meant static array as in declaration/assignment that is not followed for dynamic array. I'm new to C, sorry for the confusion! — kelsonic
– kelsonic, Commented Jan 10, 2023 at 10:24

0___________ · Accepted Answer · 2023-01-09 11:08:56Z

You can, but you do not do this properly.

Using memcpy:

 memcpy(fields, (struct user_profile[]){{"zach", "roberts", 59}, {"mike", "fisher", 19}}, sizeof(fields));

You can simply assign structures:

 fields[0] = (struct user_profile){"zach", "roberts", 59}; fields[1] = (struct user_profile){"mike", "fisher", 19};

Both methods use compound literals

Thanks for the correction, I was looking for it. And how about when length of the fields is more than 10, do I have to peform assignment seperately from fields[0]...fields[10]? What will be the best option out of both?

Collectives™ on Stack Overflow

How can I assign to new values to static array in C?

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related