Structure in a Structure and Array - c

Question

I have a few problems with the following assignments:
a)
Define a new data type tpos for storing the position of a solid in the two dimensional plane in
single precision. Afterwards define another new data type tsolid that can store the weight of
a solid in double precision and its position in the two dimensional plane. Use tpos for defining
the position component of tsolid.
b)
Define an array of length two of type tsolid. The positions and weights of both solids (array
elements) shall now be read from the keyboard by using the scanf function. For checking
correctness of your program, display the array content on the screen.
So far i have:
#include <stdio.h>
#include <stdlib.h>
struct tpos
{
float xy
};
struct tsolid
{
struct tpos;
double m;
};
int main()
{
struct tsolid array[2];
return 0;
}
How do I Proceed now? Already tried a few things, but sadly they didnt work out. The text basically says i have to save 1 solid in 1 array element, right? But how can i save pos x , pos y, and the weight m all in 1 array element and then print them all at the same time? Do i have to use a pointer ?

Answer 1

First of all, if you need to store "two dimensional plane", you should use two elements inside struct.
Other thing is that you don't access struct elements by saying struct tpos; - you should use tpos xy.
Repaired code:
#include <stdio.h>
#include <stdlib.h>
struct tpos
{
float x;
float y;
};
struct tsolid
{
tpos xy;
double m;
};
int main()
{
tsolid array[2];
return 0;
}
When it comes to scanf and displaying content you need to decide yourself on the "output layout".
And you access certain parts of the "element" by using
array[i].m;
array[i].xy.x;
array[i].xy.y;

Answer 2

tpos needs two members, one for the each coordinate.
tsolid needs a name for the tpos member.
Then write a loop that asks for each value, puts them in the array, and another loop that prints the values from the array.
#include <stdio.h>
struct tpos
{
float x, y;
};
struct tsolid
{
struct tpos position;
double mass;
};
int main()
{
struct tsolid array[2];
for (int i = 0; i < 2; i++) {
printf("Enter x, y, and mass for object %d:\n", i+1);
scanf("%f %f %lf", &array[i].position.x, &array[i].position.y, &array[i].mass);
}
printf("You entered:\n");
for (int i = 0; i < 2; i++) {
scanf("x = %f, y = %f mass = %lf\n", array[i].position.x, array[i].position.y, array[i].mass);
}
return 0;
}