面试中的几个小问题
1．对stl中list封装（参考1）；
2．对重要C函数实现（参考2）；
//memset
void *memset(void *buffer, int c, int count)
{
char* p = (char*)buffer;
while(count--)
*p++ = (char)c;
return buffer;
}
//memcpy
void * memcpy(void *dst,const void *src,int count)
{
void * ret = dst;
while (count--)
{
*(char *)dst = *(char *)src;
dst = (char *)dst + 1;
src = (char *)src + 1;
}
return(ret);
}
//memmove
/**//*
memmove()由src所指定的内存区域赋值count个字符到dst所指定的内存区域。
src和dst所指内存区域可以重叠，但复制后src的内容会被更改。函数返回指向dst的指针。
*/
void * memmove(void * dst,const void * src,int count)
{
void * ret = dst;
if (dst <= src || (char *)dst >= ((char *)src + count))
{
while (count--)
{
*(char *)dst = *(char *)src;
dst = (char *)dst + 1;
src = (char *)src + 1;
}
}
else
{
dst = (char *)dst + count - 1;
src = (char *)src + count - 1;
while (count--)
{
*(char *)dst = *(char *)src;
dst = (char *)dst - 1;
src = (char *)src - 1;
}
}
return(ret);
}
char * __cdecl strcpy(char * dst, const char * src)
{
char * cp = dst;
while( *cp++ = *src++ ) ;
return( dst );
}
char * strcat (char * dst, char * src)
{
char * cp = dst;
while( *cp )
++cp; /**//* Find end of dst */
while( *cp++ = *src++ )
/**//* Copy src to end of dst */
return( dst );
}
int strlen(const char * str )
{
const char *p = str;
while( *p++ ) ;
return( (int)(p - str - 1) );
}
//strcmp
int strcmp(const char *string1, const char *string2 )
{
int ret;
while( ( ret=*(unsigned char *)string1++ -*(unsigned char *)string2++)==0 && string1 );
return ret;
}
3．用C 写一个输入的整数,倒着输出整数的函数,要求用递归方法
void fun( int nNum)
{
printf( "%d", nNum%10 );
nNum /= 10;
if(nNum<=0)
{
return;
}
fun( nNum );
}
4．其他
参考
1. Clist封装函数
STL介绍 http://blog.csdn.net/sunny_chenpeng/article/details/5449426
介绍Clist http://blog.csdn.net/dream199029/article/details/4221577
封装 http://www.cppblog.com/changshoumeng/archive/2010/05/08/114822.aspx
2. C函数重写 http://www.cppblog.com/changshoumeng/archive/2010/05/08/114822.aspx
http://blog.csdn.net/wsh6759/article/details/7048106