Talk:Determine if a string is numeric: Difference between revisions
Talk:Determine if a string is numeric (view source)
Revision as of 17:45, 15 September 2021
, 2 years ago→Assembly implementation is harder than I thought
m (→Exact definition of IsNumeric?: fixed typo.) |
Puppydrum64 (talk | contribs) |
||
| (2 intermediate revisions by 2 users not shown) | |||
Line 144:
2
</pre>
== Assembly implementation is harder than I thought==
The way I see it, the code will need to do the following:
Read the first character.
* If it's a null terminator, the program ends and the string is not numeric.
* If it's a minus sign, that's valid and so we can continue
* If it's a decimal point, that's valid and we can continue. However, the presence of a decimal point must be recorded. If the string contains a second decimal point it stops being numeric.
* If it's not a number, at this point the string is not numeric. Otherwise continue.
Read the second character.
* If it's the terminator, the string is numeric if the first character was a numeral. If the first character was a minus sign or decimal point, the string is not numeric.
* If the second character is a numeral, continue.
* If the second character is a decimal point, continue if we haven't seen one already. If there is more than one decimal point the string is not numeric.
* If the second character is anything else, the string is not numeric.
Loop through the rest of the string.
* If we encounter the terminator, the string is numeric.
* If we encounter a numeral, continue.
* If we encounter a second decimal point, the string is not numeric.
* If we encounter anything besides a numeral, the null terminator, or the first occurrence of a decimal point, the string is not numeric.
I've attempted this in both 8086 and z80 but it ends up looking like spaghetti no matter what I do.
: @[[User: Puppydrum64]]: Uhm, is this task even applicable for assembly? I don’t thinks so. You know, depending on the assembler used there are ''several'' ways to write numeric literals. In NASM, for instance, I can write <tt>0b0110_1101</tt>. There simply isn’t ''a/the'' programming language “8086 assembly” ''defining'' how to write numeric literals. What you are attempting to do, though, is rather writing an assembly function that accepts a null-terminated string that represents a valid numeric literal ''in C'' (and many ''other'' programming languages), but not “8086 assembly”, you know what I mean? [[User:Root|Root]] ([[User talk:Root|talk]]) 18:10, 20 August 2021 (UTC)
I get what you mean. I figured at least attempting something that represents a valid numeric literal in higher-level languages was as close as I could get. Throwing in the towel and just saying "This is assembly, there are no rules" would disqualify it from almost everything. --[[User:Puppydrum64|Puppydrum64]] ([[User talk:Puppydrum64|talk]]) 17:45, 15 September 2021 (UTC)
| |||