KMP算法

//KMP#include<iostream>#include<cstdio>#include<cstring>#include<string.h>void get_next(char *T,int *next){next[1] = 0;int j = 1;int i = 0;while(j < T[0])//T[0]存放字符串的长度，j为后缀，i为前缀{if(0 == i||T[i] == T[j]){i++;j++;if(T[i]!=T[j]){next[j] = i;}else{    next[j] = next[i];}}else{i = next[i]; //回溯     }// 前缀是固定的，后缀的是相对的}}//返回子串T在主串S第pos个字符后的位置,若不存在则返回0int Index_KMP(char *S,char *T){    int i = 1;int j = 1;int next[255];get_next(T,next);while(i<=S[0]&&j<=T[0]){     if(0 == j||S[i]==T[j]){    i++;j++;}else{    j = next[j];//用模式匹配中next[j]位置去匹配}}if(j>T[0]){    return i-T[0];}else{    return 0;}}int main(){    char ss[255] = " abcdeasdwa";char tt[255] = " abcd";int sl = strlen(ss)-1;int tl = strlen(tt)-1;    ss[0] = sl;tt[0] = tl;int flag = 0;    int pos = Index_KMP(ss,tt);    if(pos!=0)   {       printf("能够匹配\n位置为%d\n",pos);   flag = 1;   }if(!flag){    printf("不匹配\n");}system("PAUSE");}