22.10 (Number of prime numbers) Programming Exercise 22.8 stores the prime numbers in a file named PrimeNumbers.dat. Write a program that finds the num-
ber of prime numbers that are less than or equal to 10 , 100 , 1,000 , 10,000 ,
100,000 , 1,000,000 , 10,000,000 , 100,000,000 , 1,000,000,000 , and
10,000,000,000 . Your program should read the data from PrimeNumbers.dat.
ber of prime numbers that are less than or equal to 10 , 100 , 1,000 , 10,000 ,
100,000 , 1,000,000 , 10,000,000 , 100,000,000 , 1,000,000,000 , and
10,000,000,000 . Your program should read the data from PrimeNumbers.dat.
import java.io.*; public class Exercise10 { public static void main(String[] args) throws IOException { DataInputStream input = new DataInputStream(new BufferedInputStream(new FileInputStream("PrimeNumbers.dat"))); long result = 0; for (long i = 10; i <= 10000000000L; i *= 10) { long number = 0; try { while((number = input.readLong()) < i) result++; System.out.println(i + " - " + result); result++; } catch (EOFException e) { System.out.println(number + " - " + result); break; } } input.close(); } }
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