[C] assert

     
   維護(assertion)敘述

        當自己寫的函式庫要提供他人使用時，適當的利用維護敘述，可以建立安全的使用
        介面，避免他人因為使用不當，而造成不可預期的後果。
        C 語言有自己的維護函式－ assert() ，使用方法如下：

           assert(total < 1000);

        當程式執行到該行時，若 total < 1000 則程式可以繼續執行；若
        total >= 1000 ，則會秀出維護錯誤訊息的字串，並結束程式。
        維護字串包含有：判斷式子、程式檔名及該行的行號。
       緊記使用前要引入前置檔 assert.h
   
--------------------------------------------------------------------------------------------------

   Advanced example:
 

1. #include <stdio.h>
2. #include <assert.h>
3. #define TRUE 1
4. #define FALSE 0
5. int
6. find_char( char **strings, int value )
7. {
8. assert( strings != NULL );
9. /*
10. ** For each string in the list ...
11. */
12. while( *strings != NULL ){
13. /*
14. ** Look at each character in the string to see if
15. ** it is the one we want.
16. */
17. while( **strings != '\0' ){
18. if( *(*strings)++ == value )
19. return TRUE;
20. }
21. strings++;
22. }
23. return FALSE;
24. }

[C] gets

gets與scanf 功能都是讀入字元,
但scanf不吃空白, 即如果輸入 "Lam with c",
scanf只會讀入"Lam" ,

遇到空白後的字一概不理;
相反地 , gets 可以讀入埋空白後面的字.







-----------------------------------------------

#include <stdio.h>

int main(void)

{

    char s[20];

    printf("請輸入連續的字元....\n");   

    gets(s);

    printf("剛剛輸入的字串： %s\n", s);

     

    return 0;

}

[C] 二維陣列(char)

1) you can use 2D char array in this way

char name[5][100];

each line in the 2D array is an array of char with size = 100

for(i=0;i<5;i++)  
{
    printf(" Enter a name which you want to register\n");  
    scanf("%99s",names[i]);
}

2) You can use array of pointers in this way

char *name[5];

each element in the array is a pointer to a string (char array). you have to assign each pointer in the array to a memory space before you call scanf()

for(i=0;i<5;i++)  
{
    names[i]=malloc(100);  
    printf(" Enter a name which you want to register\n");  
    scanf("%99s",names[i]);
}

3) if you compile with gcc and gcc version >2.7 then your scanf() can allocate memory by using "%ms" instead of "%s"

char *name[5];
for(i=0;i<5;i++)  
{
    printf(" Enter a name which you want to register\n");  
    scanf("%ms",&names[i]);
}


文章出處:http://stackoverflow.com/questions/17466563/two-dimensional-array-of-characters-in-c