爱华网1.Copyright 1990 Software Development Systems,Inc
char *strstr(const char *s1, const char *s2){int len2;if( !(len2 = strlen(s2)) )return(char *)s1;for( ; *s1; ++s1){if(*s1 == *s2 && strncmp(s1, s2,len2) == 0 )return (char *)s1;}return NULL;}
2.Copyright 1986 - 1999 IAR Systems . All rightsreservedchar *strstr(const char *s1, const char *s2){int n;if(*s2){while(*s1){for( n=0; *(s1+n) == *(s2+n); n++){if( !*(s2 + n +1) )return (char *)s1;}s1++;}return NULL;}elsereturn (char *)s1;}
举例
//strstr.c#include <syslib.h>#include <string.h>main(){char*s="Golden Global View";
char*l="lob";
char*p;
clrscr();
p=strstr(s,l);
if(p)
printf("%s",p);
else
printf("NotFound!");
getchar();
return0;
} 语法：*strstr(str1,str2)
str1:被查找目标 string expression to search.
str2:要查找对象 Thestring expression to find.
该函数返回str2第一次在str1中的位置，如果没有找到，返回NULL
Thestrstr() function returns the ordinal position within str1 of thefirst occurrence of str2. If str2 is not found in str1, strstr()returns 0.
例子：
功能：从字串”string1 onexxx string2 oneyyy”中寻找”yyy”
(假设xxx和yyy都是一个未知的字串)
char*s=” string1 onexxx string2 oneyyy”;
char*p;
p=strstr(s,”string2”);
if(p==NULL)printf(“Not Found!”);
p=strstr(p,”one”);
if(p==NULL)printf(“Not Found!”);
p+=strlen(“one”);
printf(“%s”,p);
说明：如果直接写语句p=strstr(s,”one”)，则找到的是onexxxstring2 oneyyy，不符合要求
所以需采用二次查找法找到目标
实现
char*mystrstr(char *s1 , char *s2){
if(*s1==0){if(*s2)return(char*)NULL;
return (char*)s1;
}while(*s1)
{
int i=0;
while(1)
{
if(s2[i]==0) return s1;
if(s2[i]!=s1[i]) break;
i++;
}
s1++;
}
return (char*)NULL;
}
