while

 public class TestWhile {

     /**
      * 测试循环
      */
     public static void main(String[] args) {
         int a=1;
         while(a<=100){
             System.out.println(a);
             a++;
         }
         System.out.println("while循环结束了 ");
         //1+2+3+4+5....+100=?
         int b=1;
         int sum=0;
         while(b<100){
             //sun+=b;
             sum=sum+b;
             b++;
         }
         System.out.println("从1加到100的和是:"+sum);

     }
 }