Colinear pointa

Question

have array of points and i have to check if there is any colinear three points. I tried with 3 for loops but it throws an null pointer exception. Here is the code
For(i=0;i<length-2;i++)
For(j=i+1;j<length-1;j++)
For(z=j+1;z<length;z++)
{
//declaring y1, y2...
If((y1-y2) *(x1-x3) ==(y1-y3) *(x1-x2))
{
//do something
}

}
Any help will be appreciated, ty

Answer 1

to find whether 3 points are collinear or not , then just find slope of line forming by them ... [U need only 2 pts to find slope] ... if slope equates then are collinear else not
//no need of loops ... when we can make simple 1-liner
👉(x2-x1)/(y2-y1)==(x3-x2)/(y3-y2)