不显示删除回复显示所有回复显示星级回复显示得分回复 使用while循环语句计算1+1/2!+1/3!+...1/20!之和
不明白a = a*(1.0/i);这行代码public class Example_02 {
public static void main(String args[])
{
double sum = 0,a = 1;
int i = 1;
while(i <= 20)
{
sum = sum+a;
i = i+1;
a = a*(1.0/i);
}
System.out.println(sum);
}
}
不明白a = a*(1.0/i);这行代码public class Example_02 {
public static void main(String args[])
{
double sum = 0,a = 1;
int i = 1;
while(i <= 20)
{
sum = sum+a;
i = i+1;
a = a*(1.0/i);
}
System.out.println(sum);
}
}
如果不用 a = a*(1.0/i)的话,你想啊1/2!在Java中结果是零,要得到正确结果用1.0/2!才能得到小数值
当i=2时,sum=1+1/(1*2),a=1/(1*2);
当i=3时,sum=1+1/(1*2)+1/(1*2*3),a=(1*2*3);
.......
明白了吧?