(1) 编写程序,使用for循环语句计算8+88+888+···前20项之和。代码如下:
public class exercise2 { public static void main(String args[]) { long i = 1,sum = 0,a = 8,item = a; long n = 10; for(i=1;i<=n;i++) { sum = sum+item; item = item*10+a; } System.out.println("sum= "+sum); } }
(2)编写程序,输出满足1+2+3+4+5+···+n<8888的最大正整数n。代码如下:
public class exercise2 { public static void main(String args[]) { int i; int sum = 0; int num = 0; for(i=1;i<8888;i++) { if(sum>8888) { break; }num = i-1; sum = sum+i; } System.out.println("最大正整数为:"+num); } }