以下是必需的程式。
示例public class Tester {
public static void main(String args[]) {
int i, m = 0, flag = 0;
int n = 41;// it is the number to be checked
m = n / 2;
if (n == 0 || n == 1) {
System.out.println(n + " not a prime number");
} else {
for (i = 2; i <= m; i++) {
if (n % i == 0) {
System.out.println(n + " not a prime number");
flag = 1;
break;
}
}
if (flag == 0) {
System.out.println(n + " is a prime number");
}
}
}
}
輸出結果41 is a prime number.