Quadrat special primes: Difference between revisions
Added Go
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(Added Go) |
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</pre>
=={{header|Go}}==
{{trans|Wren}}
<lang go>package main
import (
"fmt"
"math"
)
func sieve(limit int) []bool {
limit++
// True denotes composite, false denotes prime.
c := make([]bool, limit) // all false by default
c[0] = true
c[1] = true
// no need to bother with even numbers over 2 for this task
p := 3 // Start from 3.
for {
p2 := p * p
if p2 >= limit {
break
}
for i := p2; i < limit; i += 2 * p {
c[i] = true
}
for {
p += 2
if !c[p] {
break
}
}
}
return c
}
func isSquare(n int) bool {
s := int(math.Sqrt(float64(n)))
return s*s == n
}
func commas(n int) string {
s := fmt.Sprintf("%d", n)
if n < 0 {
s = s[1:]
}
le := len(s)
for i := le - 3; i >= 1; i -= 3 {
s = s[0:i] + "," + s[i:]
}
if n >= 0 {
return s
}
return "-" + s
}
func main() {
c := sieve(15999)
fmt.Println("Quadrat special primes under 16,000:")
fmt.Println(" Prime1 Prime2 Gap Sqrt")
lastQuadSpecial := 3
gap := 1
count := 1
fmt.Printf("%7d %7d %6d %4d\n", 2, 3, 1, 1)
for i := 5; i < 16000; i += 2 {
if c[i] {
continue
}
gap = i - lastQuadSpecial
if isSquare(gap) {
sqrt := int(math.Sqrt(float64(gap)))
fmt.Printf("%7s %7s %6s %4d\n", commas(lastQuadSpecial), commas(i), commas(gap), sqrt)
lastQuadSpecial = i
count++
}
}
fmt.Println("\n", count+1, "such primes found.")
}</lang>
{{out}}
<pre>
Same as Wren example.
</pre>
=={{header|Julia}}==
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