判斷輸入的數字是不是素數:
public class SuShu
{
public static void main(String[] args){
java.util.Scanner s=new java.util.Scanner(System.in);
int i=s.nextInt();
boolean isSuShu=true; //標記;
for(int j=2;j<i;j++)
{
if(i%j==0)
{
isSuShu=false;
break;
}
}
System.out.println(isSuShu ? i+"是素數" : i+"是非素數");
}
}
尋找10000以內的素數:
public class SuShu
{
public static void main(String[] args)
{
int count =0;
for(int i=2;i<=10000;i++){
boolean isSuShu=true;
for(int j=2;j<i;j++){
if(i%j==0){
isSuShu=false;
break;
}
}
if(isSuShu){
System.out.print(i+",");
count++;
if(count%8==0){
System.out.println();
}
}
}
}
}