1：for 循环：
package cn.work;public class Work1 {public static void main(String[] args) {int n = 0;for (int i = 0; i <=100 ; i++) {if (i%2==0){n = n + i;}}System.out.println("100以内的偶数和为"+n);}
}
2：while 循环
package cn.work;public class Work2 {public static void main(String[] args) {int i = 0;int n = 0;while(i<=100){i++;if(i%2==0){n = n+i;}}System.out.println("100以内的偶数和为"+n);}
}
3：do…while 循环
package cn.work;public class Work2 {public static void main(String[] args) {int i = 0;int n = 0;while(i<=100){i++;if(i%2==0){n = n+i;}}System.out.println("100以内的偶数和为"+n);}
}
运算结果为
