Question

i need a phone number with 9 digits but those digits should use only one time and be dividable by 3-5-7-11-13-17 numbers.the phone number must not contain 0. Write a code with c sharp.

note: answer is 869143275. i need to find this phone number

Answer 1

//C# program

using System;
class Main {
    public static bool isValid(int num){
        bool [] digits = new bool[10];
        bool valid = true;
        for(int i=0;i<10;i++)digits[i] = false;
        while(num > 0){
            digits[num%10] = true;
            num/=10;
        }
        for(int i=1;i<10;i++){
            valid &= digits[i];
        }
        return valid & !digits[0];
      
    }
static void Main() {
    for(int i=100000000 ; i<=999999999;i++){
        if(i%3==0 && i%5==0 && i%7==0 && i%11==0 && i%13==0 && i%17==0){
            if(isValid(i)) Console.WriteLine(i);
        }
    }
}
}