Structure within structure

We can have a structure variable as a member of another structure.

Example

Let's create a structure to store the coordinates (x,y).

Example

struct coordinate
{
    int x;
    int y;
};

Using two coordinates, we can draw a line { (x1,y1), (x2,y2) }.

To achieve that, we can create another structure and store two coordinates(struct coordinates variable).

Like below,

Example

struct line
{
    struct coordinate c1;
    struct coordinate c2;
};

structure within structure line example


Accessing structure members

Using below method, we can access the structure members.

(outer structure variable).(inner structure variable).members

structure within structure in c

In our case,

Example

To access X
struct line variable. struct coordinate variable.x

To access Y
struct line variable. struct coordinate variable.y

Let's create a variable for struct line.


struct line l;

Example

To access x and y of coordinate 1 (c1),

l.c1.x
l.c1.y

Similarly for coordinate 2 (c2),

l.c2.x
l.c2.y


Let's find the distance between the two coordinates

Distance = √ (x2-x1)2 + (y2-y1)2

Example

#include<stdio.h>
//To use sqrt and pow function
#include<math.h>

int main()
{
    float distance;

    //To store x and y
    struct coordinate
    {
        int x;
        int y;
    };

    //To store two coordinates
    struct line
    {
        struct coordinate c1;
        struct coordinate c2;
    };

    //structure line variable
    struct line l;

    //get coordinate 1
    printf("Enter c1(x and y)\n");
    scanf("%d%d",&l.c1.x,&l.c1.y);

    //get coordinate 2
    printf("Enter c2(x and y)\n");
    scanf("%d%d",&l.c2.x,&l.c2.y);

    /*
     *
     *calculate distance
     *    /-----------------------
     * __/(x2-x1)^2 + (y2-y1)^2
     *
     * #include<math.h>
     * sqrt(4)   = 2     (Square root)
     * pow(x,2)  = x * x (Power)
     *
     */

    distance = sqrt(pow((l.c2.x - l.c1.x),2) + pow((l.c2.y - l.c1.y),2));

    printf("Distance = %f\n",distance);

    return 0;
}