Task: Square-free integers

C: #include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define TRUE 1
#define FALSE 0
#define TRILLION 1000000000000

typedef unsigned char bool;
typedef unsigned long long uint64;

void sieve(uint64 limit, uint64 *primes, uint64 *length) {
    uint64 i, count, p, p2;
    bool *c = calloc(limit + 1, sizeof(bool));  
    primes[0] = 2;
    count  = 1;
    
    p = 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;
        }
    }
    for (i = 3; i <= limit; i += 2) {
        if (!c[i]) primes[count++] = i;
    }
    *length = count;
    free(c);
}

void squareFree(uint64 from, uint64 to, uint64 *results, uint64 *len) {    
    uint64 i, j, p, p2, np, count = 0, limit = (uint64)sqrt((double)to);
    uint64 *primes = malloc((limit + 1) * sizeof(uint64));
    bool add;
    sieve(limit, primes, &np);
    for (i = from; i <= to; ++i) {
        add = TRUE;
        for (j = 0; j < np; ++j) {
            p = primes[j];
            p2 = p * p;
            if (p2 > i) break;
            if (i % p2 == 0) {
                add = FALSE;
                break;
            }
        }
        if (add) results[count++] = i;
    }
    *len = count;
    free(primes);
}

int main() {
    uint64 i, *sf, len;
    
    sf = malloc(1000000 * sizeof(uint64));
    printf("Square-free integers from 1 to 145:\n");
    squareFree(1, 145, sf, &len);
    for (i = 0; i < len; ++i) {
        if (i > 0 && i % 20 == 0) {
            printf("\n");
        }
        printf("%4lld", sf[i]);
    }

    printf("\n\nSquare-free integers from %ld to %ld:\n", TRILLION, TRILLION + 145);
    squareFree(TRILLION, TRILLION + 145, sf, &len);
    for (i = 0; i < len; ++i) {
        if (i > 0 && i % 5 == 0) {
            printf("\n");
        }
        printf("%14lld", sf[i]);
    }

    printf("\n\nNumber of square-free integers:\n");
    int a[5] = {100, 1000, 10000, 100000, 1000000};
    for (i = 0; i < 5; ++i) {
        squareFree(1, a[i], sf, &len);
        printf("  from %d to %d = %lld\n", 1, a[i], len);
    }
    free(sf);
    return 0;   
}




Go: package main

import (
    "fmt"
    "math"
)

func sieve(limit uint64) []uint64 {
    primes := []uint64{2}
    c := make([]bool, limit+1) 
    
    p := uint64(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
            }
        }
    }
    for i := uint64(3); i <= limit; i += 2 {
        if !c[i] {
            primes = append(primes, i)
        }
    }
    return primes
}

func squareFree(from, to uint64) (results []uint64) {
    limit := uint64(math.Sqrt(float64(to)))
    primes := sieve(limit)
outer:
    for i := from; i <= to; i++ {
        for _, p := range primes {
            p2 := p * p
            if p2 > i {
                break
            }
            if i%p2 == 0 {
                continue outer
            }
        }
        results = append(results, i)
    }
    return
}

const trillion uint64 = 1000000000000

func main() {
    fmt.Println("Square-free integers from 1 to 145:")
    sf := squareFree(1, 145)
    for i := 0; i < len(sf); i++ {
        if i > 0 && i%20 == 0 {
            fmt.Println()
        }
        fmt.Printf("%4d", sf[i])
    }

    fmt.Printf("\n\nSquare-free integers from %d to %d:\n", trillion, trillion+145)
    sf = squareFree(trillion, trillion+145)
    for i := 0; i < len(sf); i++ {
        if i > 0 && i%5 == 0 {
            fmt.Println()
        }
        fmt.Printf("%14d", sf[i])
    }

    fmt.Println("\n\nNumber of square-free integers:\n")
    a := [...]uint64{100, 1000, 10000, 100000, 1000000}
    for _, n := range a {
        fmt.Printf("  from %d to %d = %d\n", 1, n, len(squareFree(1, n)))
    }
}