title: Program Find Slope Line
signature: programFindSlopeLine :: Double -> Double -> Double -> Double -> Double
  programFindSlopeLine x1 y1 x2 y2 = 
source_py: def program_find_slope_line(x1, y1, x2, y2):
      return (float((y2 - y1)) / (x2 - x1))
source_cpp: float program_find_slope_line(float x1, float y1, float x2, float y2) {
    return ( y2 - y1 ) / ( x2 - x1 );
  }