1、while循环
题目1：输出1～100

package struct;

public class WhileDemo01 {

    public static void main(String[] args) {
        //输出1～100
        int i = 0;

        while (i<100){
            i++;
            System.out.println(i);
        }
    }
}

题目2: 计算1+2+3+...+100？

package struct;

public class WhileDemo01 {

    public static void main(String[] args) {
        //计算1+2+...+100？

        int i = 0;
        int sum = 0;
        while (i<=100){
            sum = sum+i;
            i++;

        }
        System.out.println(sum);

    }
}