# Program to print first 10 prime numbers

Last Updated : 10 Feb, 2024

Write a program to print the first 10 prime numbers.
Note: A number N is said to be prime if it has exactly two factors i.e. 1 and the number itself N

Output Format:

2, 3, 5, 7, 9…

Approach:

Prime Test: To check whether a number N is prime we can check its divisibility with each number from 2 to N – 1, If it is divisible by any number in this range, we can conclude that N is not a prime number.

Looping until first 10 primes are not found: We can use a while loop to continue our prime check on the numbers until we print the first 10 prime numbers.

Step-by-step algorithm:

• Maintain a variable cnt = 0 to keep track of number of primes printed so far.
• Maintain a variable num = 2 to keep track of the number to be checked for prime.
• Run a loop till cnt is less than 10.
• If num is prime, increment cnt by 1.
• Increment num by 1.
• After cnt becomes 10, we have printed the first 10 prime numbers.

Below is the implementation of the above approach:

## C++

 `#include ` `using` `namespace` `std;`   `// Function to check if a number is prime or not` `bool` `isPrime(``int` `N)` `{` `    ``for` `(``int` `i = 2; i < N; i++) {` `        ``if` `(N % i == 0)` `            ``return` `false``;` `    ``}` `    ``return` `true``;` `}` `int` `main()` `{` `    ``// Variable to store number of primes printed so far` `    ``int` `cnt = 0;` `    ``// Variable to store the number to be checked for prime` `    ``int` `num = 2;` `    ``// Iterate till we have printed the first 10 primes` `    ``while` `(cnt < 10) {` `        ``// Prime Check` `        ``if` `(isPrime(num)) {` `            ``cout << num << endl;` `            ``cnt++;` `        ``}` `        ``num++;` `    ``}` `}`

## Java

 `public` `class` `PrimeNumbers {` `    ``// Function to check if a number is prime or not` `    ``public` `static` `boolean` `isPrime(``int` `N) {` `        ``for` `(``int` `i = ``2``; i < N; i++) {` `            ``if` `(N % i == ``0``) {` `                ``return` `false``;` `            ``}` `        ``}` `        ``return` `true``;` `    ``}`   `    ``// Main function` `    ``public` `static` `void` `main(String[] args) {` `        ``// Variable to store the number of primes printed so far` `        ``int` `cnt = ``0``;` `        ``// Variable to store the number to be checked for prime` `        ``int` `num = ``2``;`   `        ``// Iterate until we have printed the first 10 primes` `        ``while` `(cnt < ``10``) {` `            ``// Prime Check` `            ``if` `(isPrime(num)) {` `                ``System.out.println(num);` `                ``cnt++;` `            ``}` `            ``num++;` `        ``}` `    ``}` `}`

## Python3

 `# Function to check if a number is prime or not` `def` `is_prime(N):` `    ``for` `i ``in` `range``(``2``, N):` `        ``if` `N ``%` `i ``=``=` `0``:` `            ``return` `False` `    ``return` `True`   `# Main function` `def` `main():` `    ``# Variable to store the number of primes printed so far` `    ``cnt ``=` `0` `    ``# Variable to store the number to be checked for prime` `    ``num ``=` `2`   `    ``# Iterate until we have printed the first 10 primes` `    ``while` `cnt < ``10``:` `        ``# Prime Check` `        ``if` `is_prime(num):` `            ``print``(num)` `            ``cnt ``+``=` `1` `        ``num ``+``=` `1`   `# Run the main function` `if` `__name__ ``=``=` `"__main__"``:` `    ``main()`

## C#

 `using` `System;`   `class` `Program` `{` `    ``// Function to check if a number is prime or not` `    ``static` `bool` `IsPrime(``int` `N)` `    ``{` `        ``for` `(``int` `i = 2; i < N; i++)` `        ``{` `            ``if` `(N % i == 0)` `                ``return` `false``;` `        ``}` `        ``return` `true``;` `    ``}`   `    ``static` `void` `Main()` `    ``{` `        ``// Variable to store the number of primes printed so far` `        ``int` `cnt = 0;` `        ``// Variable to store the number to be checked for prime` `        ``int` `num = 2;`   `        ``// Iterate until we have printed the first 10 primes` `        ``while` `(cnt < 10)` `        ``{` `            ``// Prime Check` `            ``if` `(IsPrime(num))` `            ``{` `                ``Console.WriteLine(num);` `                ``cnt++;` `            ``}` `            ``num++;` `        ``}` `    ``}` `}`

## Javascript

 `// Function to check if a number ` `// is prime or not` `function` `isPrime(N) {` `    ``for` `(let i = 2; i < N; i++) {` `        ``if` `(N % i === 0)` `            ``return` `false``;` `    ``}` `    ``return` `true``;` `}`   `// Variable to store number of` `// primes printed so far` `let cnt = 0;`   `// Variable to store the number ` `// to be checked for prime` `let num = 2;`   `// Iterate till we have printed ` `// the first 10 primes` `while` `(cnt < 10) {` `    ``// Prime Check` `    ``if` `(isPrime(num)) {` `        ``console.log(num);` `        ``cnt++;` `    ``}` `    ``num++;` `}`

Output

```2
3
5
7
11
13
17
19
23
29

```

Time Complexity: O(1)
Auxiliary Space: O(1)

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