initial

main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"math/rand/v2"
+	"strings"
+)
+
+func main() {
+	onlyNum := flag.Bool("num", false, "generate only numbers (no formatting)")
+	flag.Parse()
+
+	cpf := generateCPF()
+
+	if *onlyNum {
+		fmt.Println(cpf)
+	} else {
+		fmt.Printf("%s.%s.%s-%s\n", cpf[:3], cpf[3:6], cpf[6:9], cpf[9:])
+	}
+}
+
+func generateCPF() string {
+	digits := make([]int, 11)
+
+	for i := range 9 {
+		digits[i] = rand.IntN(10)
+	}
+
+	sum := 0
+	for i := range 9 {
+		sum += digits[i] * (10 - i)
+	}
+	rem := sum % 11
+	if rem < 2 {
+		digits[9] = 0
+	} else {
+		digits[9] = 11 - rem
+	}
+
+	sum = 0
+	for i := range 10 {
+		sum += digits[i] * (11 - i)
+	}
+	rem = sum % 11
+	if rem < 2 {
+		digits[10] = 0
+	} else {
+		digits[10] = 11 - rem
+	}
+
+	var result strings.Builder
+	for _, d := range digits {
+		fmt.Fprintf(&result, "%d", d)
+	}
+	return result.String()
+}