Add Strings

Add_Strings.go

func addStrings(num1 string, num2 string) string {
        n1, n2 := len(num1), len(num2)
        n := n1
        if n < n2 {
                n = n2
        }
        res := make([]byte, n+1, n+1)
        sum := 0
        for i := 0; i <= n; i++ {
                if i < n1 {
                        sum = sum + int(num1[n1-i-1]) - int('0')
                }
                if i < n2 {
                        sum = sum + int(num2[n2-i-1]) - int('0')
                }
                res[n-i] = byte(sum%10 + int('0'))
                sum = sum / 10
        }
        if res[0] == '0' {
                return string(res[1:])
        }
        return string(res)
}

for i := 0; i < n; i++ { //it will ????
if i < n1 {
sum = sum + int(num1[n1-i-1]) - int('0')
}
if i < n2 {
sum = sum + int(num2[n2-i-1]) - int('0')
}
res[n-i] = byte(sum%10 + int('0'))
sum = sum / 10
}