Java Program to display first n or first 100 prime numbers

Java Program to display first n or first 100 prime numbers

Program to display first n prime numbers

import java.util.Scanner;

class PrimeNumberDemo
{
   public static void main(String args[])
   {
      int n;
      int status = 1;
      int num = 3;
      //For capturing the value of n
      Scanner scanner = new Scanner(System.in);
      System.out.println("Enter the value of n:");
      //The entered value is stored in the var n
      n = scanner.nextInt();
      if (n >= 1)
      {
         System.out.println("First "+n+" prime numbers are:");
         //2 is a known prime number
         System.out.println(2);
      }

      for ( int i = 2 ; i <=n ;  )
      {
         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )
         {
            if ( num%j == 0 )
            {
               status = 0;
               break;
            }
         }
         if ( status != 0 )
         {
            System.out.println(num);
            i++;
         }
         status = 1;
         num++;
      }         
   }
}

Output:

Enter the value of n:
15
First 15 prime numbers are:
2
3
5
7
11
13
17
19
23
29
31
37
41
43
47

Program to display first 100 prime numbers
To display the first 100 prime numbers, you can either enter n value as 100 in the above programOR write a program like this:

class PrimeNumberDemo
{
   public static void main(String args[])
   {
      int n;
      int status = 1;
      int num = 3;
      System.out.println("First 100 prime numbers are:");   
      System.out.println(2);
      for ( int i = 2 ; i <=100 ;  )
      {
         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )
         {
            if ( num%j == 0 )
            {
               status = 0;
               break;
            }
         }
         if ( status != 0 )
         {
            System.out.println(num);
            i++;
         }
         status = 1;
         num++;
      }         
   }
}

Output:

First 100 prime numbers 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
101
103
107
109
113
127
131
137
139
149
151
157
163
167
173
179
181
191
193
197
199
211
223
227
229
233
239
241
251
257
263
269
271
277
281
283
293
307
311
313
317
331
337
347
349
353
359
367
373
379
383
389
397
401
409
419
421
431
433
439
443
449
457
461
463
467
479
487
491
499
503
509
521
523
541