ch5ex6

README

= Exercise 5.6
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{badge-exercise}

Modify the `corner` function in section 3.2 of the book,
to use named results and a bare return statement.

== Test

We rename the previous implementation of `corner` into `oldcorner`.
This allows us to compare the new implementation of `corner` to the old one.

=== `Test_corner`

An opaque-box test of `corner` vs. `oldcorner`.
Given the same input, we expect the same output from both functions.
If `oldcorner` returns NaN, we skip to the next iteration so that
a new Corner implementation can resolve the issue.

=== `TestCornerReturnsNaNOrInf`

Reports for what combinations of i and j
`corner` returns an invalid number (NaN or +/-Inf).
This was an issue with the original implementation
which we fix in Exercise 3.1.

Documentation

Overview

Surface computes an SVG rendering of a 3-D surface function.

Index

• func Corner(i, j int) (sx, sy float64)
• func OldCorner(i, j int) (float64, float64)

Examples

• Corner

Functions

func Corner

func Corner(i, j int) (sx, sy float64)

Example

fmt.Printf("<svg xmlns='http://www.w3.org/2000/svg' "+
	"style='stroke: grey; fill: white; stroke-width: 0.7' "+
	"width='%d' height='%d'>", width, height)
for i := 0; i < cells; i++ {
	for j := 0; j < cells; j++ {
		ax, ay := Corner(i+1, j)
		bx, by := Corner(i, j)
		cx, cy := Corner(i, j+1)
		dx, dy := Corner(i+1, j+1)
		fmt.Printf("<polygon points='%g,%g %g,%g %g,%g %g,%g'/>\n",
			ax, ay, bx, by, cx, cy, dx, dy)
	}
}
fmt.Println("</svg>")

func OldCorner

func OldCorner(i, j int) (float64, float64)