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Thread Rules
1. This is not a "do my homework for me" thread. If you have specific questions, ask, but don't post an assignment or homework problem and expect an exact solution.
2. No recruiting for your cockamamie projects (you won't replace facebook with 3 dudes you found on the internet and $20)
3. If you can't articulate why a language is bad, don't start slinging shit about it. Just remember that nothing is worse than making CSS IE6 compatible.
4. Use [code] tags to format code blocks. |
On July 09 2012 13:00 Azerbaijan wrote:
I'm working on learning C and I made this simple number guessing game. I'm curious about the length of what I wrote and if it actually needs to tbe this long. I'm sure theres a way to compress it, maybe with functions, but im not quite there yet. I do want to know if this looks ok as far as clarity and use of functions goes. I know that scanf() is not a good choice but I'm still working on figuring out getchar() as an alternative, it still seems really abstract to me, its mostly just that that data types of confusing I think. I did manage to use getchar() and putchar() to spit out the ascii value of a character for me. SO basically i'm still a total noob but I'm having fun.
You don't need to compress it; it looks fine.
What would be more important though is just learning about the different data types and control structures (loops, if statements, switch statements, functions). scanf is perfectly fine for gathering user input when you're just learning to code. getchar will simply retrieve the first letter in the input buffer, and it waits for something to be placed into the input buffer if it is empty (things are placed into the input buffer when enter is pressed in a console program). Since getchar returns a single character you can actually just create a loop with getchar to read all the characters in the input buffer until a newline character is reached -- this reads a line from the input buffer:
char i;
while(i = getchar( ); i != '\n'; i = getchar( )) // Read each character, stop when find '\n' newline
{
printf( "%c", i ); // print retrieved characters back to the user
}
The above code will read a single line of user input and then print the line back to the user.
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On July 09 2012 16:53 Morfildur wrote:Show nested quote +On July 09 2012 16:22 opsayo wrote:
not a big fan of using ? for if statements
readability > conciseness imo :-) If you add whitespace, that single line is a lot more readable than
if (guess < number) {
lowhigh_text = "low";
} else {
lowhigh_text = "high";
}
It always depends on how it's used. With the ternary ?: operator, it's clear that the variable gets assigned either value. In the if/else case you have to check each block to check if it's really the same variable that gets assigned. While maintaining and repairing some of our legacy code, I got caught several times by code like:
if (a == b) {
temp = x;
} else {
tmp = y;
}
which is why you should use meaningful names, and not "temp" :D but yeah, the occasional ?: can replace a lot of other infrastructure code in some places.
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Hi guys, I have a question about my program in Python.
But first, can someone tell me how to make the block where I can post code properly? Like what tags I need to use? right now I don't even know how to indent, because extra spaces don't show up in my post, so I will not post any code for now.
I know C/C++ but I've just learned a bit of python(Very Noob) and I'm trying to create a tree in python.
It's not a binary tree or anything, and there is no order. Each treeNode simply has a list of treeNodes.
So first I create a treeNode object as the head, and it contains a list called "children". I have another list that contains three treeNodes(I will call them pNodes), and I used a for loop to add each of these three pNodes into the list called "children" that belongs to the treeNode that was created as the head.
I tried to debug my code with print statements and found that when I said:
treeNode.children.append(pNode)
treeNode.children[0] will be pNode, but for some reason, pNode.childen[0] also turned into pNode.
pNode.children is originally an empty list before the append, but for some reason a reference to itself was created.
Also, treeNode and pNode are definitely different objects.
Sorry I feel like my explanation is useless without posting the code, but does anyone have any guesses on what the problem may be?
The only language I know is C/C++ and it bugs me how python doesn't have pointers, I just don't know how anything works internally with python. Any help would be appreciated.
Thanks!
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Integer promotion is the number one cause of premature deaths in babies as young as –2147483647 years old.
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On July 18 2012 08:46 RoyGBiv_13 wrote:
Integer promotion is the number one cause of premature deaths in babies as young as –2147483647.
But not 64bit integers!
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On July 18 2012 07:06 Ultraliskhero wrote:
Hi guys, I have a question about my program in Python.
But first, can someone tell me how to make the block where I can post code properly? Like what tags I need to use? right now I don't even know how to indent, because extra spaces don't show up in my post, so I will not post any code for now.
I know C/C++ but I've just learned a bit of python(Very Noob) and I'm trying to create a tree in python.
It's not a binary tree or anything, and there is no order. Each treeNode simply has a list of treeNodes.
So first I create a treeNode object as the head, and it contains a list called "children". I have another list that contains three treeNodes(I will call them pNodes), and I used a for loop to add each of these three pNodes into the list called "children" that belongs to the treeNode that was created as the head.
I tried to debug my code with print statements and found that when I said:
treeNode.children.append(pNode)
treeNode.children[0] will be pNode, but for some reason, pNode.childen[0] also turned into pNode.
pNode.children is originally an empty list before the append, but for some reason a reference to itself was created.
Also, treeNode and pNode are definitely different objects.
Sorry I feel like my explanation is useless without posting the code, but does anyone have any guesses on what the problem may be?
The only language I know is C/C++ and it bugs me how python doesn't have pointers, I just don't know how anything works internally with python. Any help would be appreciated.
Thanks!
Can't help you with your python, but to post code you can simply surround it with [ code][/code] tags. That will preserve spacing and use monospaced font 
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@tec27 Thanks man! Now I can post some code =D
Ok so I wrote a small python program that demonstrates my problem and was wondering if anyone here can explain to me what is happening in my program.
class testNode:
string = ""
children = []
def __init__(self, _string):
self.string = _string
firstNode = testNode("first")
secondNode = testNode("second")
treeHead = testNode("Head")
treeHead.children.append(firstNode)
print treeHead.children[0].string
print firstNode.children[0].string
print secondNode.children[0].string
So in the program above, I made my treeNode class, and created three objects. I then appended firstNode to treeHead's children list. In the subsequent three print statements. I expect the first one to print "first" because the firstNode was appended to treeHead's children. However, I expect the next two print statements to fail because the children list in firstNode and secondNode should be empty.
My problem is that this is not the case, and that the last two print statements both also prints "first". It seems to me that the list called children in my class was made virtual or something. Anyways can anyone explain to me this behaviour? I'm very noob with python, and only know C/C++
Thanks all!
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@supereddie
Thanks man! My program works now. This python syntax looks so weird to me, at a glance it looks like the class has only a constructor and no data members lol.
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On July 21 2012 06:14 Ultraliskhero wrote:
@supereddie
Thanks man! My program works now. This python syntax looks so weird to me, at a glance it looks like the class has only a constructor and no data members lol.
That sort of is true, the instance of the class has data members, but the class itself only has a constructor method.
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I want to get into doing open source projects but can't seem to figure my way around. How does one begin working on an open source project (debugging and patches)? Do you just try to create a project on your own? How do you join/find a project before it begins? Do you need a certain level of expertise to start on one(I am personally a noob at c++)?
I am sorry if I seem ignorant. It seems like an overwhelming topic and I was unlucky to find only vague answers on google :/
tl;dr
I am interested in getting experience in opensource projects for experience and building my portfolio however I am still a "nub" in the programming community in c++. Have explored the concept/topic but still unsure and overwhelmed by the degree of knowledge it seems to require to start debugging/patching/working on an opensource...How do I get rid of that feeling of fear and being useless(I wouldn't even know how to find bugs let alone fix them)?
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On July 24 2012 06:21 heroyi wrote:
I want to get into doing open source projects but can't seem to figure my way around. How does one begin working on an open source project (debugging and patches)? Do you just try to create a project on your own? How do you join/find a project before it begins? Do you need a certain level of expertise to start on one(I am personally a noob at c++)?
I am sorry if I seem ignorant. It seems like an overwhelming topic and I was unlucky to find only vague answers on google :/
tl;dr
I am interested in getting experience in opensource projects for experience and building my portfolio however I am still a "nub" in the programming community in c++. Have explored the concept/topic but still unsure and overwhelmed by the degree of knowledge it seems to require to start debugging/patching/working on an opensource...How do I get rid of that feeling of fear and being useless(I wouldn't even know how to find bugs let alone fix them)?
I'd say you should just do you own small projects, create tools and various applications to do different things. If you want to help work on Mozilla or something I'd feel you'd need a lot more depth in your programming skillset. You can then release the things you write as open source. That's what I'm doing
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lets say i have an integer that stores one of 4 flags. depending on the flag, i want my code to perform 4 different actions
whats the difference between using a switch and an if else if ladder?
is one of them better to use than the other?
thanks in advance.
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On July 25 2012 05:20 snively wrote:
lets say i have an integer that stores one of 4 flags. depending on the flag, i want my code to perform 4 different actions
whats the difference between using a switch and an if else if ladder?
is one of them better to use than the other?
thanks in advance.
It will depend on your language and your compiler, but I guess you ask this in terms of performance ? (Because apart from that, they both behave in the same way).
A switch statement can be optimized by your compiler into a jump table, which turns it into a single compare and a jump (in Assembly), instead of all the successive comparisons that an if/else if ladder creates.
This will happen mostly with simple switch statements with no default: value (and is compiler/language dependent).
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On July 25 2012 05:20 snively wrote:
lets say i have an integer that stores one of 4 flags. depending on the flag, i want my code to perform 4 different actions
whats the difference between using a switch and an if else if ladder?
is one of them better to use than the other?
thanks in advance.
When you say flags it sounds like you're talking about a bitfield with setting the bits for flags. In that case you'd need to use the and & operator, and can't really use a switch statement unless you were detecting combinations of bit patterns, instead of just the separate bits.
Nobody here is going to know what is faster, as it depends on the code you write and the compiler you use. You can stress test it yourself to figure out what is faster for you.
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Denar and CecilSunkure,
i was trying to ask if either one were better than the other in terms of readability and convention
(as in, using while loops instead of goto statements)
but i guess it doesnt really matter
im not doing anything where i would need to care so much about speed
thanks anyway!
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On July 25 2012 06:10 snively wrote:
Denar and CecilSunkure,
i was trying to ask if either one were better than the other in terms of readability and convention
(as in, using while loops instead of goto statements)
but i guess it doesnt really matter
im not doing anything where i would need to care so much about speed
thanks anyway!
Either one is fine
I myself like switches more.
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On July 25 2012 05:20 snively wrote:
lets say i have an integer that stores one of 4 flags. depending on the flag, i want my code to perform 4 different actions
whats the difference between using a switch and an if else if ladder?
is one of them better to use than the other?
thanks in advance.
if flags can coexist, such as READ & WRITE....
+ Show Spoiler +
#define FLAG_ONE
#define FLAG_TWO
#define FLAG_THREE
#define FLAG_FOUR
void do_something(int flags)
{
if(flags | FLAG_ONE)
if(flags | FLAG_TWO)
...
}
Otherwise:
+ Show Spoiler +use a switch & case statement
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It's a good idea to use enums and switch statements because using integers for this job only creates confusion and errors.
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^^ Definitely enums and switch statements for conciseness and readability.
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EPT
