int i = 100; while(i<=7000) { int sum = 0,j=0; string str=i.ToString(); while(j<str.Length) { sum += str[j] - 48; if (sum > 7) break; j++; } if (sum == 7) Console.Write(i+","); i++; } Console.ReadKey();
static void Main(string[] args) { int i=100; while (i<=10000) { int s = 0; while (i != 0) { s += i % 10; i /= 10; } if(s==7){ Console.WriteLine("{0}", i);} } Console.ReadKey(); }