Find midpoint of a coordinate

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A point represents a coordinate in an x-y plane. It is supported by the following functions:

Point * make_point(double x, double y)
double x_of(Point *p)
double y_of(Point *p)
void print_point(Point *p)

Write a function

Point * mid_point

that accepts two points as arguments and returns a point that is the mid-point of these two input coordinates.

What I have tried:

Test it in online simultor with below expression but couldn't get it right

mid_point(make_point(1.0, 1.0), make_point(3.0, 3.0))

my code:

Point * mid_point(Point *x, Point *y) {
    
    int mid;

    mid = make_point((x_of (x) + x_of(x) ) / 2,  (y_of(y) + y_of(y) ) / 2);
    
    print_point(mid);
    
}

Posted 18-Mar-18 0:32am

JiaWei Lee

Updated 18-Mar-18 7:53am

v2

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Comments

Patrice T 18-Mar-18 7:43am

What is the question?

3 solutions

Solution 1

Your syntax is wrong: you need to access your coordinates via the "->" operator with pointers:

C++

double x1 = x->x_off;
double y1 = x->y_off;

I'd suggest that you change the names of the function parameters to reduce confusion:

C++

Point* mid_point(Point* a, Point* b)
   {
   ...
   }

Posted 18-Mar-18 0:53am

OriginalGriff

Solution 3

You need to implement some functions like

C++

double x_of(Point *p)
{
  return p->x;
}

but this misses error handling of null pointers so

C++

double x_of(Point *p)
{
  return p ? p->x : 0;
}

should be correct.

And pay attention to memory managment when you allocate memory you must delete it.
Learn to use the debugger and the usage of print or TRACE for your homework.

Search for some tutorial on this language details.

Posted 18-Mar-18 7:54am

KarstenK

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CPallini · Accepted Answer · 2018-03-18T07:46:00

Quote:
Point * mid_point(Point *x, Point *y) {

int mid;

mid = make_point((x_of (x) + x_of(x) ) / 2, (y_of(y) + y_of(y) ) / 2);

print_point(mid);

}

Change to

Point * mid_point(Point *p, Point *q) {
    
    Point * m;

    m = make_point((x_of (p) + x_of(q) ) / 2,  (y_of(p) + y_of(q) ) / 2);
    
    print_point(m);

    return m;
}