本算法代码数很少，可是很难说清楚，本人不才，自己就不太能看懂，不可能给别人说清楚了，在此只粘贴自己的实现，以后再补注释，以免忘记。#include<stdio.h> #include<string.h> //生成next void kmp_next(char* substr,int* next); //具体算法 int kmp_search(char* src,int* next,char* substr); //试用一下 main() { char* src = "abcaabcacdcadcdjklfd"; char* substr = "abcacd"; int next[7] = {0}; int index = -1; kmp_next(substr,next); index = kmp_search(src,next,substr); printf("/n%d",index); getchar(); } void kmp_next(char* substr,int* next){ int nstrlen = strlen(substr); int i = 0, j = -1; next[0] = -1; while(i < nstrlen - 1){ if(j == -1||substr[i] == substr[j]){ i++;j++; if(substr[i] != substr[j]) next[i] = j; else next[i] = next[j]; } else j = next[j]; } } int kmp_search(char* src,int* next,char* substr){ int nsrclen = strlen(src); int nsublen = strlen(substr); int i = -1,j = -1; while(i < nsrclen && j < nsublen){ if(j == -1 || src[i] == substr[j]){ i++;j++; } else j = next[j]; } if(j == nsublen) return i - nsublen; else return -1; }
看看函数原型应该可以知道怎么用，next数组必须不能比子字符串短。
