I'm having issues grasping the concept of string and characters in MIPS. If I'm trying to loop through two strings, and concatenate two characters at a time, how would I do this?
Lets say I have
String1 = "St"
String2 = "ack"
How could I loop through to get
Sa, Sc, Sk, ta, tc, tk
Thanks in advance!
the most easy way to do this:
1)write the program with C.
2)compile it with GCC with flags "-S", and use "> xx.S" to store the assembly code to a file.
3)extract the assembly codes from "xx.S".
Wasn't able to figure it out, the MIPS environment I used had something built in apparently.
Related
In TI-BASIC, the + operation is overloaded for string concatenation (in this, if nothing else, TI-BASIC joins the rest of the world).
However, any attempt to concatenate involving an empty string raises a Dimension Mismatch error:
"Fizz"+"Buzz"
FizzBuzz
"Fizz"+""
Error
""+"Buzz"
Error
""+""
Error
Why does this occur, and is there an elegant workaround? I've been using a starting space and truncating the string when necessary (doesn't always work well) or using a loop to add characters one at a time (slow).
The best way depends on what you are doing.
If you have a string (in this case, Str1) that you need to concatenate with another (Str2), and you don't know if it is empty, then this is a good general-case solution:
Str2
If length(Str1
Str1+Str2
If you need to loop and add a stuff to the string each time, then this is your best solution:
Before the loop:
" →Str1
In the loop:
Str1+<stuff_that_isn't_an_empty_string>→Str1
After the loop:
sub(Str1,2,length(Str1)-1→Str1
There are other situations, too, and if you have a specific situation, then you should post a simplified version of the relevant code.
Hope this helps!
It is very unfortunate that TI-Basic doesn't support empty strings. If you are starting with an empty string and adding chars, you have to do something like this:
"?
For(I,1,3
Prompt Str1
Ans+Str1
End
sub(Ans,2,length(Ans)-1
Another useful trick is that if you have a string that you are eventually going to evaluate using expr(, you can do "("+Str1+")"→Str1 and then freely do search and replace on the string. This is a necessary workaround since you can't search and replace any text involving the first or last character in a string.
Is there anybody who can get me started on this? I have very very few knowledge about python and at my college python is not even taught. However, in my Linux class my instructor insists in writing a program that replaces all periods within a paragraph with a new line. I do not want you to make my homework, but I feel a bit lost with this assignment. My pre knowledge is in c and java, both introduction levels. Can you please give me a hint on even how to start on this? Thank you very much.
Python has a string method called replace. You can use it like this.
string = """this is a test. This is another. And so on."""
newstring = string.replace(".", "\n")
print(newstring)
You can try yourself here.
i´ve got small problem and before I spend even more time in trying to solve it i´d like to know if what I want to do is even possible ( and maybe input on how to do it^^).
My problem:
I want to take some text and then split it into different strings at every whitespace (for example "Hello my name is whatever" into "Hello" "my" "name" "is" "whatever").
Then I want to set every string with it´s own variable so that I get something alike to a= "Hello" b= "my" and so on. Then I want to compare the strings with other strings (the idea is to get addresses from applications without having to search through them so I thought I could copy a telephone book to define names and so on) and set matching input to variables like Firstname , LastName and street.
Then, and here comes the "I´d like to know if it´s possible" part I want it to put it into our database, this means I want it to copy the string into a text field and then to go to the next field via tab. I´ve done something like this before with AutoIT but i´ve got no idea how to tell AutoIT whats inside the strings so I guess it must be done through the programm itself.
I´ve got a little bit of experience with c++, python and BATCH files so it would be nice if anyone could tell me if this can even be done using those languages (and I fear C++ can do it and I´m just to stupid to do so).
Thanks in advance.
Splitting a string is very simple, there is usually a built in method called .split() which will help you, the method varies from language to language.
When you've done a split, it will be assigned to an array, you can then use an index to get the variables, for example you'd have:
var str = "Hello, my name is Bob";
var split = str.split(" ");
print split[0]; // is "Hello,"
print split[1]; // is "my" etc
You can also use JSON to return data so you could have an output like
print split["LastName"];
What you're asking for is defiantly possible.
Some links that could be useful:
Split a string in C++?
https://code.google.com/p/cpp-json/
I'm currently teaching myself Lua for iOS game development, since I've heard lots of very good things about it. I'm really impressed by the level of documentation there is for the language, which makes learning it that much easier.
My problem is that I've found a Lua concept that nobody seems to have a "beginner's" explanation for: nested brackets for quotes. For example, I was taught that long strings with escaped single and double quotes like the following:
string_1 = "This is an \"escaped\" word and \"here\'s\" another."
could also be written without the overall surrounding quotes. Instead one would simply replace them with double brackets, like the following:
string_2 = [[This is an "escaped" word and "here's" another.]]
Those both make complete sense to me. But I can also write the string_2 line with "nested brackets," which include equal signs between both sets of the double brackets, as follows:
string_3 = [===[This is an "escaped" word and "here's" another.]===]
My question is simple. What is the point of the syntax used in string_3? It gives the same result as string_1 and string_2 when given as an an input for print(), so I don't understand why nested brackets even exist. Can somebody please help a noob (me) gain some perspective?
It would be used if your string contains a substring that is equal to the delimiter. For example, the following would be invalid:
string_2 = [[This is an "escaped" word, the characters ]].]]
Therefore, in order for it to work as expected, you would need to use a different string delimiter, like in the following:
string_3 = [===[This is an "escaped" word, the characters ]].]===]
I think it's safe to say that not a lot of string literals contain the substring ]], in which case there may never be a reason to use the above syntax.
It helps to, well, nest them:
print [==[malucart[[bbbb]]]bbbb]==]
Will print:
malucart[[bbbb]]]bbbb
But if that's not useful enough, you can use them to put whole programs in a string:
loadstring([===[print "o m g"]===])()
Will print:
o m g
I personally use them for my static/dynamic library implementation. In the case you don't know if the program has a closing bracket with the same amount of =s, you should determine it with something like this:
local c = 0
while contains(prog, "]" .. string.rep("=", c) .. "]") do
c = c + 1
end
-- do stuff
I would like to know hot to parse a string like this "hello world" into "helloworld" using the strstrip kernel function. I am developing a Linux Kernel char device and this functions causes me a Kernel Panic (or Kernel Opss).
The way I'm using this function is the following:
char result[100];
strcpy(result, "hello world");
strstrip(result);
strstrip(&result); //Also tried this
strstrip("100+200"); //Also tried this
The Kernel error is caused as soon as the strstrip line gets executed. What is the proper way to call this function?
Actually strstrip helps to remove the white spaces at the front. It does not remove all the white spaces with in the string.
Please look at the below example.
char result[100];
strcpy(result, " hello world from stack exchange");
printk("\n before: %s",result);
strcpy(result, strstrip((char*)result));
printk("\n after: %s",result);
Hope it helps.
srtstrip() is a wrapper function for strim() (http://lxr.linux.no/linux+v3.11.2/lib/string.c#L361) in modern kernels. As it will attempt to modify the string itself, you cannot call it with a static string as you have in the third attempt.
The second attempt you have is passing a pointer to an array variable which is also a pointer. So you are passing a char** which if you look at the link above you can see is not correct.
The first attempt should not cause a kernel error, but you do not appear to be receiving the return value in a a local variable. What kind of error are you receiving? I will update this answer if you can provide that information.
In the end though as Balamurugan A points out, this function does not do what you seem to think it does. strsep() (http://lxr.linux.no/linux+v3.11.2/lib/string.c#L485) may help you out here but it will only be a stepping stone to removing all spaces. You will actually have to copy the string into a new buffer word by word as there is not way to simply "shift memory contents", as it were.