Problem with declaring a structure

Hello all,

I am kinda new at C++ programming. But I know some of the basics. I am trying to make a simple program that uses the point of line structure to caculate the midpoint of a given line. As much as this challenge may seem easy for most of you, I am having trouble finding ways to print it.

I know, if I use (x1 + x2 / 2) & (y1 + y2 / 2) for the points of the line when asked by the user, but to calculate the line and output of the coordinates of the midpoint is my problem.

PLEASE HELP!!! AHHHHH!!!!!!!
THIS PROGRAM IS MAKING ME GO CRAZY!!!

//------------------------------------------
line horizontal_line;

horizontal_line.p1.x = ???;
horizontal_line.p1.y = ???;
horizontal_line.p2.x = ???;
horizontal_line.p2.y = ???;
m = the_slope(horizontal_line);

//umm now what?

Look at p1.x and p1.y as being p1(x, y) and p2.x and p2.y as being p2(x, y). Now there are several ways in which you may want to try to find the midpoint. You may want define your own structure to organize things a bit, such as this:

struct singlepoint
{
float x;
float y;
};

and then declare it in your program:

singlepoint myuse;

and then write a function which calculates it:

void midpoint(struct line two_points, struct singlepoint one_point)
{
one_point.x = (two_points.p1.x + two_points.p2.x) / 2;
one_point.y = (two_points.p1.y + two_points.p2.y) / 2;
}

now you can do it with your code!

// Declare vars.
line hline;
singlepoint spoint;

// Initialize them.
hline.p1.x = 2;
hline.p1.y = 3;
hline.p2.x = 34;
hline.p2.y = 33;

midpoint(&hline, &spoint); // You'll want to put the & for pointers to the structs.

Now with that finished, spoint.x should equal 18 and spoint.y should equal 18; and that can be mathematically written like this:

M(18, 18)

Alright?

Thanks dubae524!

I checked it out, and came out with this...

#include <iostream.h>

//functions prototypes
void math();

int main()
{

// Declare vars.
struct point
{
float x;
float y;
};


struct linelf
{
point p1;
point p2;
};

// Initialize them.
line linelf;
float x,y;


//program code

cout << "How long is the line?(x1): " << endl;
cin >> linelf.p1.x;

cout << "How long is the line?(y1): " << endl;
cin >> linelf.p2.x;

cout << "How long is the line?(x2): " << endl;
cin >> linelf.p1.y;

cout << "How long is the line?(y2): " << endl;
cin >> linelf.p2.y;

math();


cout << "The midpoint of your line is: " << x << ","<< y <<endl;

return 0;


}

//functions
void math()
{
x=(linelf.p1.x + line.p2.x) / 2;
y=(linelf.p1.y + line.p2.y) / 2;
}


A little diffrent from what you said, but yes, works when the errors are out.

Thank you for the help

Ben