1. strtok?? 沒有考慮執行效率問題，代碼質量也比較差，不過基本算是完成了任務

static bool check( char c, const char *token );char *strtok( char *str, const char *token ){int len;static char *cur = 0;static char *next = 0;if ( token == 0 )return str;if ( str == 0 ){if ( next == 0 )return 0;cur = next;len = xl::strlen( cur );}else {len = xl::strlen( str );cur = str;}for ( int i = 0; i < len; i++ ){if ( check( cur[i], token ) ){cur[i] = '\0';next = &cur[i+1];return cur;}}char * ret = next;next = 0;cur = 0;return ret;}static bool check( char c, const char *token ){int len = xl::strlen( token );for ( int i = 0; i < len; i++ ){if ( c == token[i] )return true;}return false;}

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2. strncpy，模仿寫的，不過感覺代碼還有優化的空間，自己沒太多的測試

主要是從2個角度進行的優化

(1) 32bit內存邊界對齊

(2) 機器字長內容復制

ps. 也許寫memcpy函數會更好

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char * strncpy( char *dest, const char *src , int _len ){char *ret = dest;long n = (sizeof(long) - (long)dest % sizeof(long)) % sizeof(long); long len = _len - n; if ( len > 0 ) {for ( long i = 0; i < n; i++ ) *dest++ = *src++;} else if( len < 0 ){for ( long i = 0; i < _len; i++ )*dest++ = *src++;return ret;} while( len >= 4 ) {*((long *)dest) = *((long *)src);dest += sizeof(long);src += sizeof(long);len -= 4;}while( len > 0 ) {*dest++ = *src++;len--;}return ret;}

轉載于:https://www.cnblogs.com/dickhead/archive/2010/11/15/1877343.html

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