c programming, create dynamic array which stores pointers, struc

Question

So my problem is kinda annoying. I have to create a struc called vector, which holds a string ~ array of chars. For later use. What Ive written so far:

vector.h
// forward declare structs and bring them from the tag namespace to the ordi$
typedef struct Vector Vector;

// actually define the structs
struct Vector {
    int SortPlace;
    char LineContent[100];
};

vector.c
// Initialize a vector to be empty.
// Pre: v != NULL
void Vector_ctor(Vector *v) {
    assert(v); // In case of no vector v
    (*v).SortPlace = 0;
    (*v).LineContent[100] = {""};
}

My error message is:

vector.c: In function ‘Vector_ctor’:
vector.c:13:24: error: expected expression before ‘{’ token
  v->LineContent[100] = {""};

Since im new to c programming im kinda lost. Basically i want to create a vector with no content.

Any help would be appreciated. Greetings

(*v).foo ~> v->foo ((*v).foo is not wrong, but it's awkward to read) — Swordfish
– Swordfish, Commented Dec 4, 2018 at 20:10
in vector.h enclose your code in #ifndef VECTOR_H_INCLUDED newline #define VECTOR_H_INCLUDED and #endif. See Why include guards? — Swordfish
– Swordfish, Commented Dec 4, 2018 at 20:12
Hi Swordfish, I have included vector.h and did enclose my code.. didnt show it in code, since im quite sure its not the error — user10563354
– user10563354, Commented Dec 4, 2018 at 20:30
(*v).LineContent[100] = {""}; ===> (*v).LineContent[0] = 0; — WhozCraig
– WhozCraig, Commented Dec 4, 2018 at 20:33

Geremia · Accepted Answer · 2018-12-04 20:26:49Z

2

 v->LineContent[100]

is a char, which you are trying to initialize as though it were an array / char *.

If you already have a v,

memset(v, 0, sizeof(struct Vector));

will zero it (you'll have to #include <string.h>).

Writing

struct Vector new_vector = {0};

declares new_vector and initializes all its contents to \0.

answered Dec 4, 2018 at 20:26

Geremia

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Comments

Scott Hunter · Accepted Answer · 2018-12-04 20:11:59Z

0

You can use {} to specify the value of individual elements of the array (in this case, charts) or, as this is a special case, use""for the string (a null-terminated sequence ofcharts) to initialize it with. What you wrote was a combination of the two.

answered Dec 4, 2018 at 20:11

Scott Hunter

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