/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
using System;
public interface ISeries {
int getNext(); // return next number in series
void reset(); // restart
void setStart(int x); // set starting value
}
// Use ISeries to generate a sequence of even numbers.
class ByTwos : ISeries {
int start;
int val;
public ByTwos() {
start = 0;
val = 0;
}
public int getNext() {
val += 2;
return val;
}
public void reset() {
val = start;
}
public void setStart(int x) {
start = x;
val = start;
}
}
// Use ISeries to implement a series of prime numbers.
class Primes : ISeries {
int start;
int val;
public Primes() {
start = 2;
val = 2;
}
public int getNext() {
int i, j;
bool isprime;
val++;
for(i = val; i < 1000000; i++) {
isprime = true;
for(j = 2; j < (i/j + 1); j++) {
if((i%j)==0) {
isprime = false;
break;
}
}
if(isprime) {
val = i;
break;
}
}
return val;
}
public void reset() {
val = start;
}
public void setStart(int x) {
start = x;
val = start;
}
}
public class SeriesDemo2 {
public static void Main() {
ByTwos twoOb = new ByTwos();
Primes primeOb = new Primes();
ISeries ob;
for(int i=0; i < 5; i++) {
ob = twoOb;
Console.WriteLine("Next ByTwos value is " +
ob.getNext());
ob = primeOb;
Console.WriteLine("Next prime number is " +
ob.getNext());
}
}
}
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