一、定义

1. 函数定义：

function f_add(num_in)
    num_in = num_in + 1
    f_add = num_in
end function

用函数名来返回参数

2. 子例程定义

sub s_add(num_in)
    num_in = num_in + 1
end sub

子例程没有返回值

二、函数与子例程在参数传递上的差别

函数和子例程调用时可以有两种方式：在括号中指定参数，或使用不带括号的格式。

使用带括号的方式指定参数时，参数是按值传递的，函数或子例程中对参数的修改不会反映到参数中。而用不带括号的格式时，则函数或子例程中对参数值的改动都是实际发生的。

以下代码示范了这两种格式的差别：

num_out = 0
wscript.echo "num before sub:", num_out
‘用不带括号的格式调用子例程
s_add num_out
wscript.echo "num after sub:", num_out
wscript.echo ""

num_out = 0
wscript.echo "num before sub():", num_out
‘用带括号的格式调用子例程
s_add(num_out)
wscript.echo "num after sub():", num_out
wscript.echo ""

num_out = 0
wscript.echo "num before function:", num_out
‘用不带括号的格式调用函数
f_add num_out
wscript.echo "num after function:", num_out
wscript.echo ""

num_out = 0
wscript.echo "num before function():", num_out
‘用带括号的格式调用函数
f_add(num_out)
wscript.echo "num after function():", num_out
wscript.echo ""

sub s_add(num_in)
    wscript.echo "num in sub", num_in
    num_in = num_in + 1
    wscript.echo "num in sub", num_in
end sub

function f_add(num_in)
    wscript.echo "num in function", num_in
    num_in = num_in + 1
    wscript.echo "num in function", num_in
    f_add = num_in
end function

输出结果如下

num before sub: 0
num in sub 0
num in sub 1
num after sub: 1

num before sub(): 0
num in sub 0
num in sub 1
num after sub(): 0

num before function: 0
num in function 0
num in function 1
num after function: 1

num before function(): 0
num in function 0
num in function 1
num after function(): 0