分別使用forwhiledo？

//計(jì)算階乘的私有方法

private int jiecheng(int i){

if(i==1)

return 1;

else

return i*jiecheng(i--);

}

//for

private int sumjiechengByFor(int n)

{

int sum =0;

for(int i=1;i

{

sum +=jiecheng(i);

}

return sum;

}

//while

private int sumjiechengByWhile(int n)

{

int sum =0,i=1;

while(i

{

sum +=jiecheng(i);

i++;

}

return sum;

}

//dowhile

private int sumjiechengByDoWhile(int n)

{

int sum =0,i=1;

if(i

do

{

sum +=jiecheng(i);

i++;

}while(i

return sum;

}