In this program, you’ll learn to print all prime numbers within an interval using for loops and display it.
A positive integer greater than 1 which has no other factors except 1 and the number itself is called a prime number.
2, 3, 5, 7 etc. are prime numbers as they do not have any other factors. But 6 is not prime (it is composite) since, 2 x 3 = 6.
C# Code:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | static void Main(string[] args) { int num1, num2, count1 = 0,count2=0; Console.Write("Enter lower range: "); num1 = Convert.ToInt32(Console.ReadLine()); Console.Write("Enter upper range: "); num2 = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("Prime numbers between {0} and {1} are: ", num1, num2); Console.WriteLine("=============================================="); for (int i = num1; i < num2; i++) { count1 = 0; if (i > 1) { for (int j = 2; j < i; j++) { if (i % j == 0) { count1 = 1; break; } } if (count1 == 0) { count2++; Console.Write(i+" "); } } } Console.WriteLine(); Console.WriteLine("We found {0} prime numbers.",count2); Console.ReadKey(); } |
Output:
