Question

编写一个Java应用程序，使用for循环计算6+66+666+6666+……的前10项之和。

Answer 1

public static void main(String []args){
double sum = 0;
double x=6;
for (int i = 1; i < =10; i++) { // i为控制相加的次数，即前10项
sum += x; //将该项与之前项的和相加
x += x * 10 + 6; //控制变量，在前一项的基础上乘以10再加6即为后面一项的值
}
System.out.println("前十项之和为： " + sum); //输出结果
}

Answer 2

public class Test {
public static void main(String []args){
double i = 6;
long result=0;
long mid=0;
for(double j=0;j<10;j++){
mid += i*Math.pow(10, j);
result += mid;
}
System.out.println(result);
}
}

Answer 3

long sum = 0;
long yin = 6;
for (int i = 0; i < 10; i++) {
sum += yin;
yin += yin * 10 + 6;
}
System.out.println("Sum is " + sum);

Answer 4

public class Leijia
{
public static void main(String args[])
{
long sum = 0;
long s = 6;
for (int i = 0; i < 10; i++)
{
sum += s;
s += s * 10 + 6;
}
System.out.println(

Answer 5

long sum = 0;
long temp = 0;
for (int i=0; i<10; i++) {
temp = temp * 10 + 6;
sum += temp;
}
System.out.println("结果为"+sum);