Prints a clockwise spiral of numbers 1, 2, 3, ...

spiral.go

package main

import "fmt"

func main() {

    size := 7

    grid := make([][]int, size)
    for k := 0; k < size; k++ {
        grid[k] = make([]int, size)
    }

    mid := (size - 1)/2
    grid[mid][mid] = 1
    x, y := mid, mid

    step, count := 1, 2
    dx, dy := 0, 1
    for ; count <= size*size; step++ {
            for k := 1; count <= size*size && k <= 2; k++ {
                for i := 1; count <= size*size && i <= step; i++ {
                    x+=dx
                    y+=dy
                    grid[x][y] = count
                    count++
                }
                dx, dy = dy, dx
            }
            dx, dy = -dx, -dy
    }

    for i := 0; i < size; i++ {
        for j := 0; j < size; j++ {
            fmt.Printf("%d\t", grid[i][j])
        }
        fmt.Printf("\n")
    }
}