C 实现strcmp,strcpy,strcat函数

基于C语言的strcmp,strcpy,strcat函数的实现。C语言是一个程序员的基础，一定要重视。

char* strcat ( char * dst , const char * src )  {       char * cp = dst;      while( *cp )          cp++; /* find end of dst */     while( *cp++ = *src++ ) ; /* Copy src to end of dst *///一直到赋完'\0'     return( dst ); /* return dst */ } char* strcpy(char * dst, const char * src){char * cp = dst;while( *cp++ = *src++ ); /* Copy src over dst */return( dst );}int strcmp ( const char* src, const char* dst ){int ret = 0 ;while(!(ret = *(unsigned char *)src - *(unsigned char *)dst) && *dst)++src, ++dst;if ( ret < 0 )ret = -1 ;else if ( ret > 0 )ret = 1 ;return( ret );}