# Prime Number From 1 to 100 Program in Java

## What is a Prime Number?

A prime number is a number that is only divisible by 1 or itself. For example, 11 is only divisible by 1 or itself. Other Prime numbers 2, 3, 5, 7, 11, 13, 17….

Note: 0 and 1 are not prime numbers. 2 is the only even prime number.

### How to display prime numbers between 1 to 100 using Java Code

Program Logic:

• The main method contains a loop to check prime numbers one by one.
• The main method calls the method `CheckPrime` to determine whether a number is prime
• We need to divide an input number, say 17 from values 2 to 17 and check the remainder. If the remainder is 0 number is not prime.
• No number is divisible by more than half of itself. So, we need to loop through just numberToCheck/2. If the input is 17, half is 8.5, and the loop will iterate through values 2 to 8
• If `numberToCheck` is entirely divisible by another number, we return false, and loop is broken.
• If `numberToCheck`is prime, we return true.
• In the main method, check isPrime is `TRUE` and add to primeNumbersFound String
• Lastly, print the results
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• public static void main(String[] args) {
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• int i;
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• int num = 0;
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• int maxCheck = 100; // maxCheck limit till which you want to find prime numbers
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• boolean isPrime = true;
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• //Empty String
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• //Start loop 1 to maxCheck
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• for (i = 1; i <= maxCheck; i++) {
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• isPrime = CheckPrime(i);
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• if (isPrime) {
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• }
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• }
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• System.out.println(“Prime numbers from 1 to “ + maxCheck + ” are:”);
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• // Print prime numbers from 1 to maxCheck
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• }
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• public static boolean CheckPrime(int numberToCheck) {
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• int remainder;
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• for (int i = 2; i <= numberToCheck / 2; i++) {
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• remainder = numberToCheck % i;
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• //if remainder is 0 than numberToCheckber is not prime and break loop. Elese continue loop
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• if (remainder == 0) {
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• return false;
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• }
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• }
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• return true;
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• }
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• }

## Output:

```Prime numbers from 1 to 100 are:
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 ```

Check our program to Find Prime Numbers from Any Input Number