朴素匹配代码

#include <string>
#include<iostream>
using namespace std;
int f[20];
int fail(string &p)
{
    f[0]=-1;
for(int j=1;j<p.length();j++){
int i=f[j-1];
while(p[j]!=p[i+1]&&i>0)
i=f[i];
if(p[j]==p[i+1])
f[j]=i+1;
else
f[j]=-1;
}
return true;

}
int stringmatch(string &s,string &p)        //朴素匹配
{
int i=0;
while(i<=s.length()-p.length())
{
int j=0;
while((s[i]==p[j])&&(j<p.length()))
{
i++;
j++;
}