Java program to print prime numbers below 100

Any whole number which is greater than 1 and has only two factors i.e. 1 and the number itself, is called a prime number. Other than these two number it has no positive divisor. In this article, we will explain Java programs to print prime numbers between 1 to 100.

Few examples of prime numbers are ? 2, 3, 5, 7, 11 etc.

Steps to Print Prime numbers below 100

Follow the steps below to print prime numbers below 100 in Java ?

• Take integer variable, let's say "A"
• Divide the variable A with (A-1 to 2)
• If A is not divisible by any value (A-1 to 2), then it is a prime number.
• Repeat this for all the numbers starting from 2 to the required limit.

Example 1

The following Java program prints the prime number below 100.

public class First100Primes { public static void main(String args[]){ for(int i = 2; i<=100;){ int prime = 1; for(int loop = 2; loop <=i; loop++) { if((i % loop) == 0 && loop!=i) { prime = 0; } } if (prime != 0){ System.out.println(i +" is a prime number"); i++; } else i++; } } } 

Output

2 is a prime number 3 is a prime number 5 is a prime number 7 is a prime number 11 is a prime number 13 is a prime number 17 is a prime number 19 is a prime number 23 is a prime number 29 is a prime number 31 is a prime number 37 is a prime number 41 is a prime number 43 is a prime number 47 is a prime number 53 is a prime number 59 is a prime number 61 is a prime number 67 is a prime number 71 is a prime number 73 is a prime number 79 is a prime number 83 is a prime number 89 is a prime number 97 is a prime number 

Example 2

The is another Java program that prints the prime numbers below 100.

public class First100Primes { public static void main(String[] args) { boolean[] prime = new boolean[100]; for (int i = 2; i < 100; i++) { prime[i] = true; } // finding non-prime numbers for (int i = 2; i * i < 100; i++) { if (prime[i]) { for (int j = i * i; j < 100; j += i) { prime[j] = false; } } } System.out.println("Prime numbers below 100: "); // printing prime numbers for (int i = 2; i < 100; i++) { if (prime[i]) { System.out.print(i + " "); } } } } 

Output

Prime numbers below 100: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97