C 语言中strstr函数实例详解
strstr函数
strstr(str1,str2) 函数用于判断字符串str2是否是str1的子串。如果是,则该函数返回str2在str1中首次出现的地址;否则,返回NULL
1
2
3
|
const char * strstr ( const char * str1, const char * str2);
char * strstr ( char * str1, const char * str2);
|
库中实现的strstr
1
2
3
4
5
6
7
8
9
10
11
12
|
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a simple string" ;
char * pch;
pch = strstr (str, "simple" );
strncpy (pch, "sample" ,6);
puts (str);
return 0;
}
|
模拟实现strstr函数
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
const char * My_strstr( const char * str1, const char * str2)
{
assert (str1);
assert (str2);
while (*str1 != '\0' )
{
const char * p1 = str1;
const char * p2 = str2;
while ((*p1 != '\0' ) && (*p2 != '\0' ) && (*p1 == *p2))
{
++p1;
++p2;
}
if (*p2 == '\0' )
{
return str1;
}
++str1;
}
return NULL;
}
int main()
{
char str1[] = "a wwww qqqqqqqqqqqqqqq" ;
char str2[] = "www" ;
printf ( "%s\n" , My_strstr(str1, str2));
system ( "pause" );
return 0;
}
|
感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!
原文链接:http://blog.csdn.net/weixin_36125166/article/details/74025182