输入一个字符串,同时输入帧头和帧尾(可以是多个字符),将该字符串中合法的帧识别出来.

输入一个字符串,同时输入帧头和帧尾(可以是多个字符),将该字符串中合法的帧识别出来.

提示:帧头和帧尾分别是head和tail  字符串”asdheadhauboisoktail”中headhauboisoktail是合法帧

#include <stdio.h>

int mystrlen(const char *str)
{
int length = 0;

while (*str++)
{
length++;
}
return length;
}

char* mystrstr(const char *str, const char *sub)   //寻找字串函数
{
int n = 0;

if (sub != NULL)
{
while (*str)
{
for (n = 0; (*(str + n) == *(sub + n)); n++)
{
if (*(sub + n + 1) == '\0')
{
return (char *)str;
}
}
str++;
}
return NULL;
}
else
{
return (char *)str;
}
}

void IdenStr(char *str, char *outbuf)
{
int count = 0;
char *p1 = NULL;
char *p2 = NULL;
char *h = "head"; //祯头，桢尾
char *t = "tail";
int tlen = mystrlen(t);

p1 = mystrstr(str, h); //找到head,tail的位置
p2 = mystrstr(str, t);
p2 += tlen;

count = p2 - p1; //求出head,tail之间有多少字符
while (count)
{
*outbuf++ = *p1++; //全部存入outbuf中
count--;
}
}

int main()
{
char str[100] = {0};
char outbuf[100] = {0}; //存放处理完的字符串

printf ("Please input a string (head...tail): \n");
scanf ("%s", str);

IdenStr(str, outbuf);
printf ("The result is %s\n", outbuf); //打印结果

return 0;
}