## Java Program – Print Prime Numbers in Given Range

A number is said to be Prime Number, if it has only 1 and itself as factors. In this program, we shall try to find the factors of a number, and if it has atleast one factor other than 1 and itself, we shall decide that it is not a prime number.

In this tutorial, we shall write a Java Program that prints all prime numbers in a given range.

### Example 1 – Print All Prime Number in Given Range

In this example, we shall use the following algorithm to print all the prime numbers with in the given range, including the limits.

#### Algorithm

1. Start of Program
2. Take a range[min, max]
3. Initialize `n` with min.
4. If `n` is Prime [Call the Function – Check if Number is Prime(given below)], print `n`.
5. Increment `n`.
6. If `n` is less than or equal to `max`, go to step 4.
7. End of Program

Function – Check if Number is Prime

1. Start of Function
2. Take number in `num`.
3. Initialize `i` with 2.
4. Check if `i` is a factor of `num`. If `i` is a factor of `num`, `num` is not prime, return False. End of the function.
5. If `i` is not a factor, increment `i`. This is to check if the next number is a factor.
6. If `i` is less than `num/i`, go to step 4.
7. Return true.
8. End of Function

Example.java

```/**
* Java Program - All Prime Numbers in Given Range
*/

public class Example {

public static void main(String[] args) {
//range
int min = 2;
int max = 100;
//find all prime numbers in the given range
for(int n=min;n<=max;n++) {
//check if this number is prime
if(isPrime(n)) {
System.out.println(n);
}
}
}

public static boolean isPrime(int num) {
for(int i = 2; i <= num/i; ++i) {
if(num % i == 0) {
return false;
}
}
return true;
}
}```

Run the above Program, and you shall get the following output with all the prime numbers printed to the console, in the given range.

Output

```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```