PB入门教程A(5)

PB入门教程A

a$ = MID$ ("PowerBASIC", 4) ' returns "erBASIC" a$ = MID$ ("PowerBASIC", 4, 20) ' returns "erBASIC" a$ = MID$ ("PowerBASIC", 20) ' returns a null string a$ = MID$ ("1234567890",3,-4) ' returns "345678"

UCASE$ 函数

用途：返回文本的大写字母。 语法：s$ = UCASE$ (string_expression) 备注：

FORMAT$ 函数

用途： 返回格式化文本。

语法： x$ = FORMAT$ (num_expression [, [digits& | fmt$]]) 备注：

A$ = FORMAT$< /FONT > (123456, "00\:00\:00") ' 12:34:56

USING$ 函数

用途：返回格式化文本。

语法：sResult$ = USING$(fmtmask$掩码, expr表达式 [, expr [, ...]]) 备注：a$ = USING$ ("!", "abc") ' returns "a"

a$ = USING$ ("You owe $$#,.##", 12345.67@)' returns "You owe DIM p AS BYTE PTR

HOST ADDR "localhost" TO ip& p = VARPTR(ip&)

a$ = USING$ ("#_.#_.#_.#", @p, @p[1], @p[2], @p[3])' returns a$ = USING$ ("&=#.##############", "Pi", ATN(1)*4)' returns a$ = USING$ ("!", "AX", "BX", "CX")' returns "ABC" a$ a$

= =

USING$ USING$

("$#.##_,",

1,20,300,4)'

returns returns

$12,345.67

x$ = UCASE$ ("Beware of cats!") Result BEWARE OF CATS!

"127.0.0.1"

"Pi=3.14159265358979"

"$1.00,$20.00,$300.00,$4.00,"

("$*=#####.##_,",1,20)'

"$======1.00,$=====20.00,"