Question: I have a C struct defined as follows:

```
struct Guest {
   int age;
   char name[20];
};

```

When I created a `Guest` variable and initialized it using the following:

```
int guest_age = 30;
char guest_name[20] = "Mike";
struct Guest mike = {guest_age, guest_name};

```

I got the error about the second parameter initialization which tells me that `guest_name` cannot be used to initialize member variable `char name[20]`.

I could do this to initialize all:

```
struct Guest mike = {guest_age, "Mike"};

```

But this is not I want. I want to initialize all fields by variables. How to do this in C?

Answer: 
mike.name is a character array. You can't copy arrays by just using the = operator.

Instead, you'll need to use `strncpy` or something similar to copy the data.

```
int guest_age = 30;
char guest_name[20] = "Mike";
struct Guest mike = { guest_age };
strncpy(mike.name, guest_name, sizeof(mike.name) - 1);

```

You've tagged this question as C++, so I'd like to point out that in that case you should almost always use `std::string` in preference to `char[]`.
You can statically allocate a struct with a fixed char[] array in C. For example, gcc allows the following:

```
#include <stdio.h>

typedef struct {
    int num;
    char str[];
} test;

int main(void) {
    static test x={.num=sizeof("hello"),.str="hello"};

    printf("sizeof=%zu num=%d str=%s\n",sizeof(x),x.num,x.str);
    return 0;
}

```

And it does the right thing (though beware of the sizeof(x): it returns 4 on my machine; not the length of the total statically allocated memory).

This does not work for structs allocated from the stack, as you might suspect.