string 之 strcpy函数

 1 /*******************************************************
 2  *  strcpy and strncpy
 3  *  !! Note: *desStr = '\0' Don't forget!
 4  *******************************************************/
 5 char * Mystrcpy(char *desStr, const char *srcStr){
 6     assert(NULL != desStr && NULL != srcStr);
 7     char *address = desStr;
 8 
 9     while( (*desStr ++ = *srcStr ++));  //此条语句与下面的功能一致（值得品味）
10     //while( (*desStr ++ = *srcStr ++) != '\0');
11     //while( (*srcStr ++ ) != '\0' ){
12     //    *desStr ++ = *srcStr;
13     //}
14     //while( *srcStr )
15     //    *desStr++ = *srcStr++;
16     *desStr = '\0';
17 
18     return address;
19 }
20 
21 char * Mystrncpy(char *desStr,const char *srcStr,size_t nCount){
22     assert(NULL != desStr && NULL != srcStr && nCount <= strlen(srcStr));
23     char *address = desStr;
24 
25     while( (nCount --) && (*desStr ++ = *srcStr ++) );
26     //while(nCount --)
27     //    *desStr ++ = *srcStr ++;
28     *desStr = '\0';
29 
30     return address;
31 }