KMP算法查找串S中含串P的个数count

#include <iostream>
#include <stdlib.h>
#include <vector>
using namespace std;

inline void NEXT(const string& T,vector<int>& next)
{
    //按模式串生成vector,next(T.size())   
    next[0]=-1;            
    for(int i=1;i<T.size();i++ ){
        int j=next[i-1];
        while(T[i]!=T[j+1]&& j>=0 )
         j=next[j] ;  //递推计算
        if(T[i]==T[j+1])next[i]=j+1; 
        else next[i]=0;  //
    }   
} 
inline string::size_type COUNT_KMP(const string&  S,
                    const string&  T)
{
    //利用模式串T的next函数求T在主串S中的个数count的KMP算法
    //其中T非空，
    vector<int> next(T.size());
    NEXT(T,next);
    string::size_type index,count=0;   
    for(index=0;index<S.size();++index){      
        int pos=0;
        string::size_type iter=index;
        while(pos<T.size() && iter<S.size()){
            if(S[iter]==T[pos]){
                ++iter;++pos;
            }
            else{
                if(pos==0)++iter;              
                else pos=next[pos-1]+1;
            }   
        }//while end
        if(pos==T.size()&&(iter-index)==T.size())++count;
    } //for end
    return count;
}
int main(int argc, char *argv[])
{
    string S="abaabcacabaabcacabaabcacabaabcacabaabcac";
    string T="ab";
    string::size_type count=COUNT_KMP(S,T);
    cout<<count<<endl;
 
  system("PAUSE"); 
  return 0;
}