[算法练习]字符.字符串删除,字符提前
#include <stdio.h>size_t _strlen(char *str)
{
return (NULL == str || *str =='\0') ? 0 : _strlen(str+1) + 1;
}
//思路：只要不是星号的都交给写指针写入,忽略*
//问题可以转换为：删除字符串中的特定字符 只不过这个是从尾巴开始
char* str_TiQian(char *str)
{
if(NULL == str || *str == '\0')
return NULL;
int len = 0;
int Dst = 0;
int count = 0;
len = Dst = _strlen(str) - 1;
do
{
if(str != '*')
str = str;//这里是先执行str = str 然后才dst-1;
else
count ++;
} while (len--);
for (int i = 0; i < count; i++)
{
str = '*';
}
printf("%s\n",str);
return str;
}
//思路同上
char* str_TiQian_Ex(char* str)
{
if(NULL == str || '\0' == *str)
return NULL;
char *pRead = 0;
char *pWrite = 0;
pRead = pWrite = str + _strlen(str) - 1;
do
{
if(*pRead != '*')
*pWrite-- = *pRead;
} while (pRead-- != str);//先比较再赋值
while (pRead <= pWrite)
{
*pRead++ = '*';//先执行后面的在执行加操作
//相当于
//*pRead = '0';
//pRead ++;
}
printf("%s\n",str);
return str;
}
char* Del_speciol_ch(char *str, char ch)
{
if(NULL == str || *str == '\0')
return NULL;
char *pRead = 0;
char *pWrite = 0;
pRead = pWrite = str;
do
{
if(*pRead != ch)
*pWrite++ = *pRead;
} while (*pRead++ != '\0');
printf("%s\n",str);
return str;
}
char* Del_speciol_ch_Ex(char *str, char ch)
{
if(NULL == str || *str == '\0')
return NULL;
int sour = 0;
int dst = 0;
do
{
if(str != ch)
str = str;
} while (str != '\0');
printf("%s\n",str);
return str;
}
//用数组下标标志sub字符串,同hash原理
char* Del_Speciol_Str(char *str, char ch[], int n)
{
if( str == NULL || *str == '\0' || n == 0 || ch == '\0' )
return NULL;
char temp = {0};
for (int i = 0; i < n; ++i)
{
temp] = 1;
}
int dst = 0;
int src = 0;
do
{
if( !temp] )
{
str = str;
}
} while (str != '\0');
return str;
}
int Del_Speciol_Str_Ex(char *str, char *substr)
{
if(str == NULL || *str == '\0' || substr == NULL || substr == '\0' )
return 0;
char *pSrc = NULL;
char *pDet = NULL;
char *p,*pSub;
pSrc = pDet = str;
int count = 0;
//O(n) + O(n)
while(*pSrc)
{
p = pSrc;
pSub = substr;
while(*p && *p == *pSub)
{
p++;
pSub++;
}
if(*pSub == '\0')//==0就说明匹配成功了 成功了就将当前的指针付给pSrc指针继续找后面还有没有匹配的字符串
{
pSrc = p;
count++;
}else
{
*pDet++ = *pSrc++;
}
}
*pDet = 0;
return count;
}
void main()
{
/*char str0 = "hel*lo w*or*ld";
printf("%s\n",str0);
str_TiQian(str0);
char str1 = "***hel*l**o w*o**r*ld**";
printf("\n%s\n",str1);
str_TiQian(str1);
char str3 = "***hel*l**o w*o**r*ld**";
printf("\n%s\n",str3);
str_TiQian_Ex(str3);
char str4 = "hel***lo w*or*ld";
printf("\n%s\n",str4);
str_TiQian_Ex(str4);*/
/*printf("\n----------\nDel * \n");
char str5 = "hel***lo w*or*ld";
printf("\n%s\n",str5);
Del_speciol_ch(str5,'*');
Del_speciol_ch(str3,'*');*/
char str6 = "hel***lo w*or*ld";
char str7 = "***hel*l**o w*o**r*ld**";
printf("del_char:\n%s\n",str6);
Del_speciol_ch_Ex(str6,'*');
printf("del_char:\n%s\n",str7);
Del_speciol_ch_Ex(str7,'*');
char strTest = "MallocFree is luanmaMr.Zhou";
char ch = "luanma";
printf("del_chars:\n%s\n", strTest);
//Del_Speciol_Str(strTest,ch,5);
int subnum = Del_Speciol_Str_Ex(strTest, ch);
printf("%s\nSubNum:%d\n",strTest ,subnum);
getchar();
}
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