/**
* 用do-while计算1+1/2！+1/3！+……的前20项的和
* @Hoagn
*
*/
public class Add2 {
public static void main(String[] args) {
int i = 1, a = 1;
double sum = 0,b = 0;
do {
a = i * a;
b = 1.0 / a;
sum = sum + b;
i++;
}while(i <= 20);
System.out.println(sum);
}
}
for
/** * 用for循环计算1+1/2！+1/3！+……的前20项的和 * @author Hogan * */ public class Add1 { public static void main(String[] args) { int i = 1, a = 1; double sum = 0,b = 0; for(i = 1; i <= 20; i++) { a = i * a; b = 1.0 / a; sum = sum + b; } System.out.println(sum); } }
/**
* 用do-while计算1+1/2！+1/3！+……的前20项的和
* @Hoagn
*
*/
public class Add2 {
public static void main(String[] args) {
int i = 1, a = 1;
double sum = 0,b = 0;
do {
a = i * a;
b = 1.0 / a;
sum = sum + b;
i++;
}while(i <= 20);
System.out.println(sum);
}
}
for
/** * 用for循环计算1+1/2！+1/3！+……的前20项的和 * @author Hogan * */ public class Add1 { public static void main(String[] args) { int i = 1, a = 1; double sum = 0,b = 0; for(i = 1; i <= 20; i++) { a = i * a; b = 1.0 / a; sum = sum + b; } System.out.println(sum); } }
public class HomeWork05 {
public static void main(String[] args){
{
int i,j,k;
for(i=1;i<1000;i++)
{
int sum=0;
for(j=1;j<i;j++)
{
if(i%j==0){
sum+=j;
}
}
if(sum==i){
System.out.println(i);
}
}
}
}
}
用for循环计算8+88+888+...前10项之和。
public class demo49_4_5 {
public static void main(String[] args) {
long sum=0,item=8;
for(int i=1;i<=10;i++) {
sum = sum+item;
item = item*10+8;
}
System.out.println(sum);
}
}
public class Main {
public static void main(String args[]) {
int i=1,s=0;
while(s<8888){
i++;
s+=i;
}
System.out.println(i);
}
}
1 public class Hello { 2 3 public static void main(String[] args) { 4 int sum=0; 5 int i; 6 for(i=1;sum+i<8888;i++) { 7 sum=sum+i; 8 } 9 System.out.println("sum为："+sum); 10 System.out.println("最大正整数为："+(i-1)); 11 } 12 }
原文：https://www.cnblogs.com/hoganhome/p/11537728.html