How to create nested while loop in C#?

For a nested while loop, we have two while loops.

The first loop checks for a condition and if the condition is true, it goes to the inner loop i.e. the nested loop.

Loop 1

while (a<25) {
}

Loop 2 (inside loop1)

while (b<45){
}

To create a nested while loop, the following is the sample code.

Example

using System;
namespace Program {
   class Demo {
      public static void Main(string[] args) {
         int a=20;
         while (a<25) {
            int b=40;
            while (b<45) {
               Console.Write("({0},{1}) ", a, b);
               b++;
            }
            a++;
            Console.WriteLine();
         }
      }
   }
}

Output

(20,40) (20,41) (20,42) (20,43) (20,44)
(21,40) (21,41) (21,42) (21,43) (21,44)
(22,40) (22,41) (22,42) (22,43) (22,44)
(23,40) (23,41) (23,42) (23,43) (23,44)
(24,40) (24,41) (24,42) (24,43) (24,44)