c语言实现strcmp和strcpy

strcpy的实现代码http://hi.baidu.com/zhouwei0213/blog/item/f3a9aebeca4e0a0d18d81fad.htmlchar * strcpy(char * strDest, const char * strSrc){     if ((strDest==NULL)||(strSrc==NULL)) //[1]         throw "Invalid argument(s)"; //[2]    char * strDestCopy=strDest; //[3]    while ((*strDest++=*strSrc++)!='\0'); //[4]        return strDestCopy; }strcmp的实现代码http://blog.chinaunix.net/uid-20480343-id-1941622.htmlint my_strcmp(const char *source,const char *dest){    int ret = 0 ;    //这里的*dest判断很重要，否则二者完全相等的时候就会越界出现难以判断的情况    while( ! (ret = *( unsigned char *)source - *(unsigned char *)dest) && *dest)         source++, dest++;    if ( ret < 0 )        ret = -1 ;    else if ( ret > 0 )        ret = 1 ;    return(ret);}