在字符串中查找字符串 Strstr() StrstrSpan()

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/*
Description:
The strstr function locates the firstoccurrence in the string pointed to by s1 of the sequence of characters(excluding the terminating\
null character)in the string pointed to by s2.
Returns:
The Strstr function returns a pointer to the located string,or a null pointer if the string is not found.If s2 points to a string with\
zero length,the function return str1.
*/

char *Strstr(char *str1, char *str2)

{
        while(*str1)
        {
                char *pos = str1;
                char *s2 = str2;

                while(*s2 && *pos && (*pos == *s2))
                {
                        pos++;
                        s2++;
                }
                if(!*s2)
                        return str1;
                if(!*pos)
                        return NULL;
                str1++;
        }
        return NULL;
}

/*
Description:

在str1字符串中，同时在span个字符内，定位tr2, 如果search str1的过程中，超出了span的范围，即遍历str1中的字符个数超过了span，则查找失败，返回null。
Returns:
The Strstr function returns a pointer to the located string,or a null pointer if the string is not found.If s2 points to a string with\
zero length,the function return str1.
*/

char *StrstrSpan(char *str1, char *str2, int span)

在字符串中查找字符串 Strstr() StrstrSpan()

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原文地址：http://blog.csdn.net/ruanjianruanjianruan/article/details/45953185