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# Program to print prime numbers from 1 to N.

• Difficulty Level : Easy
• Last Updated : 21 May, 2021

Given a number N, the task is to print the prime numbers from 1 to N.
Examples:

```Input: N = 10
Output: 2, 3, 5, 7

Input: N = 5
Output: 2, 3, 5 ```

Approach:

• First, take the number N as input.
• Then use a for loop to iterate the numbers from 1 to N
• Then check for each number to be a prime number. If it is a prime number, print it.

Below is the implementation of the above approach:

## C++

 `// C++ program to display first N Prime numbers``#include ``using` `namespace` `std;` `// Function to print first N prime numbers``void` `print_primes_till_N(``int` `N)``{``    ``// Declare the variables``    ``int` `i, j, flag;` `    ``// Print display message``    ``cout << ``"\nPrime numbers between 1 and "``         ``<< N << ``" are:\n"``;` `    ``// Traverse each number from 1 to N``    ``// with the help of for loop``    ``for` `(i = 1; i <= N; i++) {` `        ``// Skip 0 and 1 as they are``        ``// neither prime nor composite``        ``if` `(i == 1 || i == 0)``            ``continue``;` `        ``// flag variable to tell``        ``// if i is prime or not``        ``flag = 1;` `        ``for` `(j = 2; j <= i / 2; ++j) {``            ``if` `(i % j == 0) {``                ``flag = 0;``                ``break``;``            ``}``        ``}` `        ``// flag = 1 means i is prime``        ``// and flag = 0 means i is not prime``        ``if` `(flag == 1)``            ``cout << i << ``" "``;``    ``}``}` `// Driver code``int` `main()``{` `    ``int` `N = 100;` `    ``print_primes_till_N(N);` `    ``return` `0;``}`

## Java

 `// Java program to display``// first N Prime numbers``class` `GFG``{``    ` `// Function to print first N prime numbers``static` `void` `print_primes_till_N(``int` `N)``{``    ``// Declare the variables``    ``int` `i, j, flag;` `    ``// Print display message``    ``System.out.println(``"Prime numbers between 1 and "``                                      ``+ N + ``" are:"``);` `    ``// Traverse each number from 1 to N``    ``// with the help of for loop``    ``for` `(i = ``1``; i <= N; i++)``    ``{` `        ``// Skip 0 and 1 as they are``        ``// neither prime nor composite``        ``if` `(i == ``1` `|| i == ``0``)``            ``continue``;` `        ``// flag variable to tell``        ``// if i is prime or not``        ``flag = ``1``;` `        ``for` `(j = ``2``; j <= i / ``2``; ++j)``        ``{``            ``if` `(i % j == ``0``)``            ``{``                ``flag = ``0``;``                ``break``;``            ``}``        ``}` `        ``// flag = 1 means i is prime``        ``// and flag = 0 means i is not prime``        ``if` `(flag == ``1``)``            ``System.out.print(i + ``" "``);``    ``}``}` `// Driver code``public` `static` `void` `main (String[] args)``{``    ``int` `N = ``100``;` `    ``print_primes_till_N(N);``}``}` `// This code is contributed by AnkitRai01`

## Python3

 `# Python3 program to display first N Prime numbers` `# Function to print first N prime numbers``def` `print_primes_till_N(N):` `    ``# Declare the variables``    ``i, j, flag ``=` `0``, ``0``, ``0``;` `    ``# Print display message``    ``print``(``"Prime numbers between 1 and "``,``                            ``N , ``" are:"``);` `    ``# Traverse each number from 1 to N``    ``# with the help of for loop``    ``for` `i ``in` `range``(``1``, N ``+` `1``, ``1``):` `        ``# Skip 0 and 1 as they are``        ``# neither prime nor composite``        ``if` `(i ``=``=` `1` `or` `i ``=``=` `0``):``            ``continue``;` `        ``# flag variable to tell``        ``# if i is prime or not``        ``flag ``=` `1``;` `        ``for` `j ``in` `range``(``2``, ((i ``/``/` `2``) ``+` `1``), ``1``):``            ``if` `(i ``%` `j ``=``=` `0``):``                ``flag ``=` `0``;``                ``break``;` `        ``# flag = 1 means i is prime``        ``# and flag = 0 means i is not prime``        ``if` `(flag ``=``=` `1``):``            ``print``(i, end ``=` `" "``);` `# Driver code``N ``=` `100``;``print_primes_till_N(N);` `# This code is contributed by Rajput-Ji`

## C#

 `// C# program to display``// first N Prime numbers``using` `System;``    ` `class` `GFG``{``    ` `// Function to print first N prime numbers``static` `void` `print_primes_till_N(``int` `N)``{``    ``// Declare the variables``    ``int` `i, j, flag;` `    ``// Print display message``    ``Console.Write(``"Prime numbers between 1 and "` `+``                                   ``N + ``" are:\n"``);` `    ``// Traverse each number from 1 to N``    ``// with the help of for loop``    ``for` `(i = 1; i <= N; i++)``    ``{` `        ``// Skip 0 and 1 as they are``        ``// neither prime nor composite``        ``if` `(i == 1 || i == 0)``            ``continue``;` `        ``// flag variable to tell``        ``// if i is prime or not``        ``flag = 1;` `        ``for` `(j = 2; j <= i / 2; ++j)``        ``{``            ``if` `(i % j == 0)``            ``{``                ``flag = 0;``                ``break``;``            ``}``        ``}` `        ``// flag = 1 means i is prime``        ``// and flag = 0 means i is not prime``        ``if` `(flag == 1)``            ``Console.Write(i + ``" "``);``    ``}``}` `// Driver code``public` `static` `void` `Main (String[] args)``{``    ``int` `N = 100;` `    ``print_primes_till_N(N);``}``}` `// This code is contributed by Rajput-Ji`

## Javascript

 ``
Output:
```Prime numbers between 1 and 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```

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