KMP算法C语言实现

#include<stdio.h>
#include<string.h>
#define maxsize 100
typedef struct
{
  char data[maxsize];
  int length;
}sqString;
void get_next(sqString t, int next[])
{
  int i = 0;
  int j = -1;
  t.length = strlen(t.data);
  next[0] = -1;
  while (i < t.length - 1)
  {
  if (j == -1 || t.data[i] == t.data[j])
  {
    i++;
    j++;
    next[i] = j;
  }
  else
  {
    j = next[j];
  }
  }
}
int KMP(sqString t1,sqString t2,int next[])
{
  int i=0, j=0;
  int len1 = strlen(t1.data);
  int len2 = strlen(t2.data);
  while (i < len1 && j < len2)
  {
  if (j == -1 || t1.data[i] == t2.data[j])
  {
    i++;
    j++;
  }
  else
  {
    j = next[j];
  }
  }
  if (j >= len2)
  return i - len2 + 1;
  else
  return -1;
}
int main()
{
  int i = 0;
  int next[100];
  sqString t1, t2;
  printf("请输入主串:");
  scanf("%s",t1.data);
  printf("请输入副串:");
  scanf("%s", t2.data);
  get_next(t2, next);
  i = KMP(t1, t2, next);
  printf("%d\n", i);
  return 0;
}