class primefinder {
public static void main(String[] args) {
// Define the variables that will be used
int n=2; /*low numbers to test*/
int n2=4; /* high numbers to test*/
int next=2; /*next numbers to test*/
int count=0; /*count of primes*/
int i; /*divisor*/
boolean prime; /*prime true or false*/
// Test the arguments
if (args.length > 0) {
try {
n = Integer.parseInt(args[0]);
} catch (NumberFormatException e) {
System.err.println("You Must Enter a Natural Number");
System.exit(1);
}
}
if (args.length > 0) {
try {
n2 = Integer.parseInt(args[1]);
} catch (NumberFormatException e) {
System.err.println("You Must Enter a Natural Number");
System.exit(1);
}
}
if (n<2) {
System.err.println("You Must Enter a Natural Number >2");
System.exit(1);
}
if (n2<2) {
System.err.println("You Must Enter a Natural Number >2");
System.exit(1);
}
// Test for prime numbers
System.out.println("Find the primes between " + n + " and "
+ n2);
System.out.println("");
next=n;
while (next <= n2) {
prime=true;
for (i=2; i*i<=next; i++) {
if(next%i==0) {
prime=false;
}
}
if(prime) {
System.out.println("The number "+ next + " is a prime");
count++;
}
next++;
}
System.out.println("");
System.out.println("There are " + count + " primes between "+
n + " and " + n2);
}
}