Original link: http://blog.chinaunix.net/uid-24103300-id-108254.htmlint strlen1 (const char *str), Char *del_char (char *str, char c);
Char *delete_string (char *str,int pos,int len);
const char *STRSTR1 (const char *src,const char *sub);
Char *strchr1 (char *str, char ch);
int chrcnt1 (const char *src,char ch);
Char *strpbk (char const *s,char const *ACCPET);
Char *strcpy1 (char *dest,const char *source);
Char *strncpy1 (char *dest,const char *source,int len);
void *memcpy1 (void* dst,const void* src,size_t count);
void *memmove1 (void* dst,const void* src,size_t count);
Char *strcat1 (char *dest,const char *src);
Char *strncat1 (char *dest, const char* src,int num);
void Sort1 (char *src,int num);
Char *strrv1 (const char *STR);
Char *strrv2 (const char *STR);
Char *strrv3 (char *str,int len);
void Revstr (char *src);
int Isrevstr (char *str);//Judging whether it is a palindrome level
void Loopmove (char *src,int N);
Char *loopmove (char *str, int num);
//////////////////////////////////////////////////////////////////////////////////
Calculate the length of a string
int strlen1 (const char *STR)
{
int len=0;
while (*str++!= ')
len++;
return Len; /* This method is more efficient than the above (self-increment two) when the string length is longer
**const Char *temp=str;//Save the first address of SRC
**while (*src++!= ');//self-increment once
**return (src-temp-1);//Returns the difference between the tail pointer and the head pointer, that is, the length
*/
}
////////////////////////////////////////////////////////////////////////////////
Removes all specified characters from a string
Two pointers are defined, the head pointer is used for recording, and p is used for string traversal;
Char *del_char (char *str,char c)
{
Char *head=null;
Char *p=null;
if (str==null)
{
return NULL;
}
HEAD=P=STR;
while (*P)
{
if (*p!=c)
{
*str++=*p;
}
p++;
}
*str= ' + ';
return head;
}
//////////////////////////////////////////////////////////////////////////////
Deletes a specified length of character from the specified position of the string
First check the legitimacy of the POS and Len, then find the POS location, delete len characters
Char *delete_string (char *str,int pos,int len)
{
Char *p=str+pos-1;//character pointing to pos position
int strlen=strlen1 (str);//Custom method
int Str_len=strlen (str);//Character length library function if ((pos<1) | | (P-STR) >strlen)//check POS is not greater than 1, or POS exceeds the string length
{
return str;
}
if ((P+LEN-STR) >strlen)//len is greater than the number of characters remaining after Pos, simply assign '% ' to POS location
{
*p= ' + ';
return str;
}
while (*p && * (P+len))//len is less than or equal to the number of characters remaining after Pos delete len characters
{
*p=* (P+len);
p++;
}
*p= ' + ';
return str;
}
///////////////////////////////////////////////////////////////////////////////
The implementation of searching STRSTR library function of strings in string
const char *STRSTR1 (const char *src,const char *sub)
{
const char *BP;
const char *SP;
if (Src==null | | sub==null)//Check the validity of SRC and sub
{
return SRC;
}
while (*SRC)
{
BP=SRC;
Sp=sub;
Do
{//Traverse sub String
if (!*SP)//If the sub string end position is reached, exit
return SRC;
} while (*bp++==*sp++);
Src+=1;
} return NULL;
}
/////////////////////////////////////////////////////////////////////////////
The STRCHR () function returns a pointer to the first occurrence of CH in STR and returns NULL when no CH is found in Str.
Char *strchr1 (char *src, Char ch)
{while ((*src!=ch) && (*SRC))
src++; return (SRC);}
////////////////////////////////////////////////////////////////////////////////
CHRCNT () to calculate the number of occurrences of a character in a string.
int chrcnt1 (const char *src,char ch)
{
int count=0;
while (*SRC)
if (*src==ch)
count++;
return count;
}
/////////////////////////////////////////////////////////////////////////
The function returns a character position that points to any one of the first matched group in Str. NULL if none is returned.
Char *strpbk (char const *s,char const *ACCPET)
{
while (*s! = ')
{
while (*accpet! = ')
if (*accpet++ = = *s)
Return (char *) s;
++s;
}
return NULL;
}
////////////////////////////////////////////////////////////////////////////////
String copy
Char *strcpy1 (char *dest,const char *source)
{
Char *srcdest=dest;//Save the first address of the target string
/*
while (*source! = ')
*dest++ = *source++;
*dest = ' + '; Notation 1
*/
while ((*dest++=*source++)! = ' + ');
return srcdest;
}
/////////////////////////////////////////////////////////////////////////
String copy of the specified length
Char *strncpy1 (char *dest,const char *source,int len)
{
Char *srcdest=dest;//Save the first address of the target string
while (*source! = ' + ' && len--)
*dest++ = *source++;
*dest = ' + '; return srcdest;
}
////////////////////////////////////////////////////////////////////////////
Memory Copy implementation copy non-overlapping memory block void* memcpy1 (void* dst,const void* src,size_t count)
{
char* pbto = (char*) DST;
char* Pbfrom = (char*) src;
ASSERT (dst!= NULL && src! = NULL);//cannot exist null pointer
ASSERT (pbto >= pbfrom+count | | pbfrom >= pbto + count);//Prevent memory overlap (overlap)
while (count--> 0)
{
*pbto++ = *pbfrom++;
}
return DST;
} //////////////////////////////////////////////////////////////////////////
Memmove implementation move a byte, src source data can not be preserved
void* memmove1 (void* dst,const void* src,size_t count)
{
char* pbto = (char*) DST;
char* Pbfrom = (char*) src;
ASSERT (DST! = NULL && src! = null);//cannot exist null pointer
if (DST <= src | | pbto >= PBFROM + count)//no overlap case, direct copy
{
while (count--> 0)
{
*pbto++ = *pbfrom++;
}
}
Else
{
pbto = pbto + count-1;//overlap case, copy from high address to low
Pbfrom = Pbfrom + count-1;
while (count--> 0)
{
*pbto--= *pbfrom--;
}
}
return DST;
}
/////////////////////////////////////////////////////////////////
Memset: Sets the first count bytes of the memory area indicated by buffer to character C
void * Memset (void* buffer, int c, int count)
{
char* pvto= (char*) buffer;
ASSERT (buffer! = NULL);
while (count-->0)
*pvto++= (char) C;
return buffer;
}
/////////////////////////////////////////////////////////////////////////////
Implementation of string comparison strcmp library function
int strcmp1 (const char *src,const char *DST)
{
int ret;
while (!) ( ret=* (unsigned char *) src-* (unsigned char *) DST) && *DST)//Cycle compare two characters for equality
{
++SRC;
++DST;
}
if (ret<0) ret=-1;
Else
if (ret>0) ret=1;
return (ret);
}
/////////////////////////////////////////////////////////////////////////
Connecting two strings implementation of STRCAT library function
Char *strcat1 (char *dest,const char *src)
{
char *temp = dest;
while (*dest! = ')
dest++;
while ((*dest++ = *src++)! = ' + ');
return temp;
}
////////////////////////////////////////////////////////////////////////////
Connect two specified number of strings implementation of STRNCAT library function
Char *strncat1 (char *dest, const char* src,int num)
{
char *temp = dest;
while (*dest! = ')
dest++;
while ((*dest++ = *src++)! = ' + ' && num--);
return temp;
}
////////////////////////////////////////////////////////////////////////////
The sorting and swapping of strings bubbles:
void Sort1 (char *src,int num)
{
int i,j;
int tmp=0;
for (i=0;i<num;i++)
{
for (j=i+1;j<num;j++)
{
Tmp=src[i];
SRC[I]=SRC[J];
src[j]=tmp;
}
}
}
//////////////////////////////////////////////////////////////////////////
Inverse of a string
Char *strrv1 (const char *STR)
{
int i;
int Len=strlen (str);
char c;
Char *tmp=new char[len+1]; strcpy (TMP,STR);
for (I=0;i {
C=tmp[i];
TMP[I]=TMP[LEN-I-1];
Tmp[len-i-1]=c;
}
return TMP;
}
Pointer implementation
Char *strrv2 (const char *STR)
{
char c;
Char *tmp=new char[strlen (str) +1];
strcpy (TMP,STR); Char *ret=tmp;
Char *p=tmp+strlen (str)-1;
while (P>TMP)
{
c=*tmp;
*tmp=*p;
*p=c;
--p;
++tmp;
}
return ret;
}
Recursive implementation
Char *strrv3 (char *str,int len)
{
if (len<=1)
return str;
Char t=*str;
*str=* (str+len-1);
* (str+len-1) =t; Return (Strrv3 (str+1,len-2)-1);}
///////////////////////////////////////////////////////////////////////
Reverses ABCDEFGH but does not change the internal structure of the word
void Revstr (char *src)
{
Char *start=src,*end=src,*ptr=src;
while (*ptr++! = ')
{
if (*ptr== ' | | | *ptr== ')
{
End=ptr-1;//end point to end of word
while (Start<end)
Swap (*start++,*end--);//reverse the letter of the word
start=end=ptr+1;//point to the beginning of the next word
}
} Start=src,end=ptr-2;//start points to the beginning, end points to the end
while (Start<end)
{
Swap (*start++,*end--);//reverse the entire string
}}
//////////////////////////////////////////////////////////////////////
Determine if it is a palindrome level
int Isrevstr (char *str)
{
int I,len;
int found=1;
if (str==null)
{
return-1;
}
Len=strlen (str);
for (I=0;i {
if (* (str+i)!=* (str+len-i-1))
{
Found=0;
Break
}
}
return found;
}
/////////////////////////////////////////////////////////////////////////
String Loop Right Shift
void Loopmove (char *src,int N)
{
int i=0;
Char *tmp=null;
int strlen=0;
Char *head=src;
while (*src++)
Strlen=src-head-1;
N=n%strlen;
tmp= (char*) malloc (n);
for (i=strlen-1;i<n;i++)
{
Tmp[i]=head[strlen-n+i];
}
for (i=strlen-1;i>=n;i--)
{
HEAD[I]=HEAN[I-N];
}
for (i=0;i<n;i++)
{
Head[i]=tmp[i];
}
Free (TMP);
}
////////////////////////////////////////////////////////////////////////
String right (not implemented with library functions)
Char *loopmove (char *str, int num)
{
Char temp[100]= "";
int i = 0;
int len = 0;
Request length
for (i=0;str[i]!=0;i++)
len++;
Save last Num characters
for (i=0;i<num;i++)
{
Temp[i] = Str[len-num+i];
}
Move the first len-num character backward by num bytes
for (i=0;i<len-num;i++)
{
Str[len-1-i] = Str[len-1-i-num];
}
Put the saved post num characters at the front of str
for (i=0;i<num;i++)
{
Str[i] = Temp[i];
}
return str;
}
String manipulation _ (Do not use library functions)
