The process of Learning a "tool"

1. To know why to Learn? (motivation)

2. To Learn how to run.

3. To learn how to use it's basic functions.

4. To learn how to apply this tool to your work.

5. Practice makes perfect.

6. To understand the theory behind this tool.

array pointer and pointer array

#define COLS 5 /* assume array size = 5*/

int (*xptr)[COLS];  /* this is an array's pointer */

int *xptr[COLS]; /* this is a pointer array */

function pointer example

#include
#include

void func(int);

main(){
void (*fp)(int);

fp = func;

(*fp)(1);
fp(2);

exit(EXIT_SUCCESS);
}

void
func(int arg){
printf("%d\n", arg);
}

illustrate a[x] means *(a+x) equals *(x+a) equals x[a]

code:

int main(void)

{

char a[4]="123";

a[2]='x';

puts(a);

2[a]='y';

puts(a);

return 0;

}

executive result:

12x

12y

[Research] List the keyword

List the keyword:

o. write a sentence about your topic

o. pull out the keywords and phrases in the sentence above and list them separately.

o. start expanding the list with related terms and synonyms.

o. Are there any larger categories that might lead you to information?

o. Are there any words or phrases that are more specific?

o. now you have a beginning list of key words and phraeses to begin searching for

information.

o. Synonyms and Related Terms

o. Larger Categories

o. Smaller Categories

skype codec policy

最近想要去驗證skype的一個機制, 通常如果要驗證, 就會想要自己製造出同樣的環境來模擬skype的環境, 理想上要製造出一模一樣的環境, 這樣結果當然會是最正確, 但是既然是模擬, 就不可能一模一樣, 因為一模一樣就不叫模擬了, 叫做實現.

現在問題就是, 我到底可以做到多像, 多接近skype本身的codec policy. 首先, 我要先研究skype的機制, 目前已經初步判定他可能的機制, 接下來要製造出和實驗一模一樣的設定值, 然後套用在模擬的環境中, 在各方面設定都相同的情況下, 做出的結果理論上也應該要相似.

目前所遇到的難點在於, 不是非常確定skype codec的環境設置, 如此一來, 模擬跟實驗的結果就理當會有差異了. 我們先假設skype有按照codec的標準走, 而我們的模擬也要確定有按照codec標準走, 先做到這樣, 再看看結果,