（scheme）(d) (on-parallels? x1 y1 x2 y2 x3 y3 x4 y4), a character of prospect parameters (the x and y values of foul-mouthed points), produce penny if the course through points (x1,y1) and (x2,y2) is correspondent to the course through points (x3,y3) and (x4,y4). You may take that points (x1, y1) and (x2, y2) are clear, as are (x3, y3) and (x4, y4). (Note: this character can conservation any of the characters defined overhead, beside should concede a rectify tally equable in the cases where points-slope or points-intercept would miscarry.
The proposal is to confront slop of courses. If brace courses are correspondent then there slop must be corresponding inadequately they are not attributable attributable attributable correspondent.
Bool correspondent (x1,y1,x2,y2,x3,y3,x4,y4)
// Slop of primary course
double m1 =(y2-y1)/(x2-x1);
//Slope of course brace
double m2= (y4-y3)/(x4-x3);