1 /*******************************************************
 2  *  strcat and strncat
 3  *  Note:  while(*desStr) desStr++;  OK
 4  *         while(*desStr ++);        ERROR!
 5  *         *desStr = '\0' 可有可无，不过最好加上
 6  *******************************************************/
 7 char * Mystrcat(char *desStr, const char *srcStr){
 8     assert(NULL != desStr && NULL != srcStr);
 9     char *address = desStr;
10 
11     while(*desStr) desStr++;             //(1)OK! 
12     //while(*desStr ++);                 //(2)ERROR! 后缀++ 运算符较 间接操作符 * 优先级高，在跳出循环时指向了'\0'之后
13     while(*desStr ++ = *srcStr ++);
14     // *desStr = '\0';                  //?为何可有可无（道理同上）
15 
16     return address;
17 }
18 
19 char * Mystrncat(char *desStr, const char *srcStr, size_t nCount){
20     assert(NULL != desStr && NULL != srcStr && nCount <= strlen(srcStr));
21     char *address = desStr;
22 
23     while( *desStr )
24         *desStr ++;
25     while( nCount-- )
26         *desStr ++ = *srcStr ++;
27     *desStr = '\0';
28 
29     return address;
30 }