查找文件位置

#include<stdio.h>
#include<string.h>

int main()
{
char str1[30], str2[30], str3[30], str4[40], *p;
int pos;
printf("Please input string1: ");
gets(str1);
printf("Please input string2: ");
gets(str2);
pos=strspn(str1,str2);
printf("The position you want to find is: %d\n",pos);
printf("Please input string3: ");
gets(str3);
printf("Please input string4: ");
gets(str4);
p=strstr(str3,str4);
if(p)
{
printf("str3 include str4\n");
}
else
{
printf("can not find str4 in str3!");
}
printf("\n");
return 0;
}