void NativeStrMatching( ElemType Target[], ElemType Pattern[] )
{register int TarLen = 0; // Length of Targetregister int PatLen = 0; // Length of Pattern// Compute the length of Patternwhile( '\0' != Pattern[PatLen] )PatLen++;while( '\0' != Target[TarLen] ){int TmpTarLen = TarLen;for(int i=0; i<PatLen; i++){if( Target[TmpTarLen++] != Pattern[i] )break;if( i == PatLen-1 )cout<<"Native String Matching,pattern occurs with shift "<<TarLen<<endl;}TarLen++;}
}

void NativeStrMatch(const string& target,const string& pattern){int n=target.size();int m=pattern.size();for(int i=0;i<n;i++){int k=i;int j;for(j=0;j<m&&target[k]==pattern[j];k++,j++);if(j==m){cout<<"Native string Matching occurs at "<<i<<endl;}}
}

// Compute Prefix function
void CptPfFunc( ElemType Pattern[], int PrefixFunc[] )
{register int iLen = 0; // Length of Pattern[]while( '\0' != Pattern[iLen] )iLen++;int LOLP = 0; // Lenth of longest prefixPrefixFunc[1] = 0;for( int NOCM=2; NOCM<iLen+1; NOCM++ ) // NOCM represent the number of characters matched
    {while( LOLP>0 && (Pattern[LOLP] != Pattern[NOCM-1]) )LOLP = PrefixFunc[LOLP];if( Pattern[LOLP] == Pattern[NOCM-1] )LOLP++;PrefixFunc[NOCM] = LOLP;}
}

void KMPstrMatching( ElemType Target[], ElemType Pattern[] )
{int PrefixFunc[MAX_SIZE];register int TarLen = 0;register int PatLen = 0;// Compute the length of array Target and Patternwhile( '\0' != Target[TarLen] )TarLen++;while( '\0' != Pattern[PatLen] )PatLen++;// Compute the prefix function of Pattern
    CptPfFunc( Pattern, PrefixFunc );int NOCM = 0; // Number of characters matchedfor( int i=0; i<TarLen; i++ ){while( NOCM>0 && Pattern[NOCM] != Target[i] )NOCM = PrefixFunc[NOCM];if( Pattern[NOCM] == Target[i] )NOCM++;if( NOCM == PatLen ){cout<<"KMP String Matching,pattern occurs with shift "<<i - PatLen + 1<<endl;NOCM = PrefixFunc[NOCM];}}
}

#include <iostream>
#include <string>
using namespace std;
//compute prefix function
void CptPfFunc(const string& pattern,int* prefix){size_t m=pattern.size();int j=0;//length of longest prefixprefix[1]=0;for(int i=2;i<=m;i++){while(j>0&&pattern[j]!=pattern[i-1])j=prefix[j];if(pattern[j]==pattern[i-1])j++;prefix[i]=j;}
}
void KMPstrMatch(const string& target,const string& pattern){int n=target.size();int m=pattern.size();int *prefix=new int[m+1];CptPfFunc(pattern,prefix);int j=0;for(int i=0;i<n;i++){while(j>0&&pattern[j]!=target[i])j=prefix[j];if(pattern[j]==target[i])j++;if(j==m){cout<<"KMP string Matching occurs at "<<i-j+1<<endl;j=prefix[j];}}delete [] prefix;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void table(char*); // 建立前进表
int search(int, char*, char*); // 搜寻关键字
void substring(char*, char*, int, int); // 取出子字符串
int skip[256];
int main(void) { char str_input[80]; char str_key[80]; char tmp[80] = {'\0'}; int m, n, p; printf("请输入字符串："); gets(str_input); printf("请输入搜寻关键字："); gets(str_key); m = strlen(str_input); // 计算字符串长度n = strlen(str_key); table(str_key); p = search(n-1, str_input, str_key); while(p != -1) { substring(str_input, tmp, p, m); printf("%s\n", tmp); p = search(p+n+1, str_input, str_key); } printf("\n"); return 0;
}
void table(char *key) { int k, n; n = strlen(key); for(k = 0; k <= 255; k++) skip[k] = n; for(k = 0; k < n - 1; k++) skip[key[k]] = n - k - 1;
}
int search(int p, char* input, char* key) { int i, m, n; char tmp[80] = {'\0'}; m = strlen(input); n = strlen(key); while(p < m) { substring(input, tmp, p-n+1, p); if(!strcmp(tmp, key)) // 比较两字符串是否相同return p-n+1; p += skip[input[p]]; } return -1;
}
void substring(char *text, char* tmp, int s, int e) { int i, j; for(i = s, j = 0; i <= e; i++, j++) mp[j] = text[i]; tmp[j] = '\0';
}