如何删除字符串中某个字符后的所有内容？

Question

如何删除字符串中“？”之后的所有内容?到目前为止，我的代码搜索“？”。我该如何从那里着手？

这是我的代码。

INCLUDE Irvine32.inc

.data
source BYTE "Is this a string? Enter y for yes, and n for no",0

.code
main PROC

mov edi, OFFSET source
mov al, '?'                  ; search for ?
mov ecx, LENGTHOF source
cld
repne scasb       ; repeat while not equal
jnz quit
dec edi           ; edi points to ?

end main

Answer 1

您可以替换“？”之后的所有内容由零，所以“？”之后的所有字符已被“删除”：

INCLUDE Irvine32.inc

.data
source BYTE "Is this a string? Enter y for yes, and n for no",0

.code
main PROC

mov edi, OFFSET source
mov al, '?'                  ; search for ?
mov ecx, LENGTHOF source
cld
repne scasb       ; repeat while not equal
jnz quit
dec edi           ; edi points to ?

;REPLACE ALL CHARACTERS BY "AL" (ZERO) STARTING WHERE "EDI" WAS AND
;FINISH WHEN "ECX" == 0.
mov al, 0         ;<=====================================
repne stosb       ;<=====================================

end main

请注意我们是如何使用 EDI 和 ECX 搜索“？”后的值的。