【c程序】经典函数（strcpy、strlen及memcpy）的实现

#include <stdio.h> char* strcpy(char *strDest, const char* strSrc) { char *p=NULL; if(strDest == NULL || strSrc == NULL) { return NULL; } p = strDest; while((*strDest++ = *strSrc ++) != '\0'); return p; }

 

int getStrLen(const char* str) { int len = 0; while( *str ++ != '\0') { len ++; } return len; } void *mymemcpy(void *dst,const void *src,size_t num) { assert((dst!=NULL)&&(src!=NULL)); byte * psrc = (byte *)src;//byte 既为unsigned char类型 byte * pdst = (byte *)dst; while(num-->0) { *pdst++ = *psrc++; } return dst; }