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@ayinlaaji
Created January 7, 2020 17:41
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Validating credit card numbers
package main
import (
"fmt"
"strconv"
)
func luhnCheck(cardNo int) bool {
toStr := strconv.Itoa(cardNo)
var cardDigits []int
for i := range toStr {
x, _ := strconv.Atoi(string(toStr[i]))
cardDigits = append(cardDigits, x)
}
cardLen := len(cardDigits)
var reversedDigits []int
l := cardLen - 1
for i := l; i > -1; i-- {
reversedDigits = append(reversedDigits, cardDigits[i])
}
var oddParity int
var evenParity int
for i := range reversedDigits {
if (i+1)%2 > 0 {
oddParity += reversedDigits[i]
} else {
m := reversedDigits[i] * 2
if m > 9 {
t := strconv.Itoa(m)
g := 0
for i := range t {
x, _ := strconv.Atoi(string(t[i]))
g += x
}
evenParity += g
} else {
evenParity += m
}
}
}
total := oddParity + evenParity
return total%10 == 0
}
func main() {
start := "517214"
end := "7805"
maxNo := 9997
total := 0
cardNos := []int{}
for i := 0; i <= maxNo; i++ {
//todo bug padd numbers less that 10
sC := start + strconv.Itoa(i) + end
cardNo, _ := strconv.Atoi(sC)
isValid := luhnCheck(cardNo)
if isValid {
cardNos = append(cardNos, cardNo)
total += 1
}
}
fmt.Println(cardNos, total)
}
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