C programming structure access [closed] - c

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I found this line in Linux Audio drivers soc-core.c inside sound folder:
int regsize = codec->driver->reg_word_size * 2;
Can anybody please explain the meaning of * 2?

Multiply the contents of codec->driver->reg_word_size by 2. I guess this is a translation between size in words to size in bytes.

Multiplies that value by 2. That's all it does

Well, I can just guess, but it looks like this:
codec is a pointer to a structure, which has a pointer to another structure in driver, which has a member variable reg_word_size (which it seems is, like the name says, the size of a register word). This value gets doubled (*2).
This could be, like the other answer says, a conversion between bytes and words. However, it could probably also just mean that this regsize should be twice as big as the reg_word_size.

Related

Analyzing Part of a String [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I'm new to C and I have an assignment where I have to build a dictionary (Linked List in a way). Basically the user inputs several words,year and their definition this:
Example:
love_#_2004_#_LOVING
trade_#_2001_#_INVEST
etc...
And basically I need a function to scan the definition (Ex: INVEST)
and gives me the word trade.
If the definition is related to more than only one word to give me back all the words it relates to.
What sort of a function do I need to scan these strings?
If the word you search is always the last one and the formatting is always the same, then use strtok with _ and copy the last entry, which holds the string you are looking for.

Can you use operators to define the size of an array in C? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
Right now I'm trying to write a program, and one part of the it involves expanding an existing array by copying values from a previous array into an array with a larger size.
The way I'm doing this by using an int variable which is defined in a previous point int the program by user input.
int[x] array;
int[x + 1] array2;
Will this work, or do I have to initialize a separate int variable with value of x + 1?
The correct syntax is:
int array[x];
int array2[x+1];
C 1999 and later supports this (with the value of x determined at run time), although it is optional in C 2011. Some compilers (of questionable quality) do not support it.
The space available for objects of this sort is typically limited to one to eight mebibytes or so, and that space must also serve for other program needs, so it should be used only for small arrays.

Two to the power of some large number [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
Can anyone tell me how to find (2^101100111000)%1000000007 in C?
There is a problem in which we have to convert a number into binary(1<=N<=600000) and find
2^(binary representation of N)modulo1000000007.
The values you are talking about will not fit into a standard long on any architecture, so you will have to use an arbitrary precision maths library such as GMP.
Hmm, just read Zong's answer... he's pointing to a more efficient method... haven't finished reading through the article but it looks like the better way to go...

C: Creating a given number of variables automatically [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
Is it possible to create a C-function that creates automatically a given number of variables? How are variables named?
Variables are an artifact of your source code. During runtime (which is when your function actually executes) there is only memory and registers. Maybe you want an array of a certain length?
The solution is to use array.
example:
//n is number of variables
int *var;
var= malloc(sizeof(int) * n);
variables are named var[0], var[1]....var[n-1]
If by "variables" you mean "global variables outside the scope of the function", and by "create" you mean "declare and define", then NO.
Do you mean like the register_globals 'feature' in PHP? Thank goodness, no.

How to store an array in heap? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Closed 8 years ago.
This question appears to be off-topic because it lacks sufficient information to diagnose the problem. Describe your problem in more detail or include a minimal example in the question itself.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Improve this question
I'm a C beginner and I'm learning "heap" currently. One thing confuse me is can we store an array in heap? If we can, how?
Say for example:
int main(void) {
char sentence[] = "Please move me to heap.";// I want to store this sentence in heap
printf("%s\n", sentence);
}
Can somebody clarify this point to me? Thanks in advance.
Please have a look at this C tutorial and then have a look at malloc.
There is an example use of malloc here. If you are learning, it is better to read a slightly longer tutorial than for us to give you the answer in code as the former will better your understanding.

Resources