！！跪求！！！1+2+...+n 用常规方法，数组，自定义三种方法编写vb！！

VB的哦
1 用for
private sub form_click()
dim m as long,n as long
dim k as long
dim i as long,j as long
k=20
for i=1 to k
for j=1 to i
m=m+1
next
n=n+m
next

print n
end sub

2
用do 或while 这两个相似，只是语法有一点儿不同
private sub form_click()
dim n as long
dim j as long
dim i as long
dim s as long
n=20
i=0
do while i<>n
i=i+1
j=0
do while j<>i
j=j+1
loop
s=s+j
loop

print s
end sub

3用whle wend 和DO一样，我就不写了

1.sum = n(n+1)/2,等差数列求和
2.sum = 0;for(int i=1;i<=n;++i) sum += i;,普通的方法
3.int s(int n)
{
if (n == 1)
return 1;
else
return n + s(n-1);
}

嘿嘿，meiyou学过，也不知道怎么弄

1.dim n%,sum%
sum=n*(n+1)/2
2.dim i%,sum%,n%
for i=1to n
sum =sum+1
next i

3.dim a()%,n%,i%
re