数质数及优化程序 





 1 package text;
 2 
 3 public class TestPrimeNumber {
 4     public static void main(String[] args){
 5         boolean flag = false;
 6         long start = System.currentTimeMillis();
 7         l:for(int i = 2; i < 100000; i++){//从0遍历到100
 8             for(int j = 2; j <= Math.sqrt(i); j++){//127,判断i是否为质数
 9                 if(i % j == 0){
10                     continue l;
11                 }
12             }
13             System.out.println(i);
14 
15         }
16         long end = System.currentTimeMillis();//17097
17         System.out.println("所花费的时间为：" + (end - start));
18     }
19 }






 


 1 package text;
 2 
 3 public class TestPrimeNumber {
 4     public static void main(String[] args){
 5         boolean flag = false;
 6         long start = System.currentTimeMillis();
 7         for(int i = 2; i < 100000; i++){//从0遍历到100
 8             for(int j = 2; j <= Math.sqrt(i); j++){//127,判断i是否为质数
 9                 if(i % j == 0){
10                     flag = true;
11                     break;//1635
12                 }
13             }
14             if(!flag){
15                 System.out.println(i);
16             }
17             flag = false;//改回判断旗帜
18         }
19         long end = System.currentTimeMillis();//17097
20         System.out.println("所花费的时间为：" + (end - start));
21     }
22 }
23 /*
24  * 循环内加添加 break
25  * 判断改变为 Math.sqrt(i)
26  */




 







        

        

            posted on 
2018-01-26 02:11 
Aoki894 
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