Array in struct

Question

I want an array in a struct but I am unsure how to do it. I can only use one array in the struct.

typedef struct 
{
    int arr[10];
} coords;


coords x;

printf("Enter X coordinates: ");

scanf("%d", x.arr[0]);
scanf("%d", x.arr[1]);
scanf("%d", x.arr[2]);
...

My problem is how do I also enter the X values in the array? I was first thinking of a two dimensional array arr[10][10] but it wouldn't work because I have some calculations to do on the X values.

Is the proper way just do define a new object like coords x; and just do it all over?

Basically I want the struct to contain one (1) array. I want the struct to contain x and y coordinates for a map, which the user inputs. Later in the program I want to do calculations with ONLY the x values.

I don't understand (almost) anything. Can you rephrase?

Kiril Kirov
– Kiril Kirov

2013-11-20 12:56:45 +00:00
Commented Nov 20, 2013 at 12:56 — Kiril Kirov
– Kiril Kirov, Commented Nov 20, 2013 at 12:56
I updated the OP, maybe something got clearer. :)

user3005287
– user3005287

2013-11-20 13:03:34 +00:00
Commented Nov 20, 2013 at 13:03 — user3005287
– user3005287, Commented Nov 20, 2013 at 13:03
Can you give us an example of the data you want to use?

robbie_c
– robbie_c

2013-11-20 13:23:12 +00:00
Commented Nov 20, 2013 at 13:23 — robbie_c
– robbie_c, Commented Nov 20, 2013 at 13:23

Michael · Accepted Answer · 2013-11-20 13:19:17Z

3

You can use a couple of arrays in one struct in a following way:

typedef struct 
{
    int x[10];
    int y[10];
} coords;


coords c;

printf("Enter a couple of X coordinates: ");
scanf("%d", &c.x[0]);
scanf("%d", &c.x[1]);

printf("Enter a couple of Y coordinates: ");
scanf("%d", &c.y[0]);
scanf("%d", &c.y[1]);

Note that in scanf() you should pass pointers to array elements and not elements.

Also you can do it using one 2-D array (X_COOR and Y_COOR can be removed):

#define X_COOR 0
#define Y_COOR 1
typedef struct 
{
    int coords[2][10];
} coords;    

coords c;

printf("Enter a couple of X coordinates: ");
scanf("%d", &c.coords[X_COOR][0]);
scanf("%d", &c.coords[X_COOR][1]);

printf("Enter a couple of Y coordinates: ");
scanf("%d", &c.coords[Y_COOR][0]);
scanf("%d", &c.coords[Y_COOR][1]);

edited Nov 20, 2013 at 13:19

answered Nov 20, 2013 at 13:04

Michael

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4 Comments

user3005287 Over a year ago

But I can only have one array in the struct, not several.

Michael Over a year ago

@user3005287 Then how do you want to store them in one array? Interleaved? Mean x,y,x,y...

Michael Over a year ago

@user3005287 One 2-d array is in the answer.

Natan Streppel Over a year ago

@user3005287 if Michael's answer here doesn't answers your question yet, then I believe you'll have to rephrase it again

unwind · Accepted Answer · 2013-11-20 13:24:49Z

1

A nicer solution is of course to do an array of struct, since the core thing you're interested in (a coordinate expressed as a pair of values) can be modelled well as a struct:

typedef struct {
  int x, y;
} coordinate;

then you can declare an array easily enough:

coordinate my_coords[100];

answered Nov 20, 2013 at 13:24

unwind

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Comments

haccks · Accepted Answer · 2013-11-20 13:06:08Z

0

You code is fine except you have to place & operator before the argument of each scanf.

scanf("%d", &x.arr[0]);

For Y co-ordinates you should have to define another array inside your structure.

answered Nov 20, 2013 at 13:06

haccks

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Comments

user694733 · Accepted Answer · 2013-11-20 13:23:50Z

0

Create another struct for array element:

typedef struct 
{
    int x;
    int y;
} coord;

typedef struct 
{
    coord arr[10];
} coords;

Usage:

scanf("%d", &x.arr[0].x);

answered Nov 20, 2013 at 13:23

user694733

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