字符串-模式匹配-KMP算法

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAXSIZE 256
typedef struct string {
    
    
	char chs[MAXSIZE];
	int length;
}String;
int f[MAXSIZE];
int LengthCHAR(char* s) {
    
    
	int i = 0;
	while ((s[i]) != '\0') {
    
    
		i++;
	}
	return i;
}
//模式匹配KMC算法
int IndexKMP(String s, String p, int pos) {
    
    
	int i = pos, j = 0; 
	int n = s.length,
		m = p.length;
	while (i < n && j<m) {
    
    
		if (j == -1 || s.chs[i] == p.chs[j]) {
    
    
			i++;
			j++;
		}
		else {
    
    
			j = f[j];
		}
		
	}
	return ((j == m) ? i - m : -1);
}
//计算失败函数
void Fail(String p, int* f) {
    
    
	int j = 0, k = -1;
	f[0] = -1;
	while (j < p.length) {
    
    
		if (k == -1 || p.chs[j] == p.chs[k]) {
    
    
			j++; k++;
			f[j] = k;
		}
		else {
    
    
			k = f[k];
		}
		if (j == p.length) {
    
    
			break;
		}
	}
}
void PrintString(String* s) {
    
    
	printf("Output the String:\n");
	printf("%s\n", s->chs);
}
void main() {
    
    
	String* s, * p;
	int size_ss, size_pp;
	char  ss[MAXSIZE] = "zzzzzzabcabcaabcabcabbacb";  //长度不得大于 MAXSIZE
	char  pp[MAXSIZE] = "abcabcabbac"; //长度不得大于 MAXSIZE
	s = (String*)malloc(sizeof(String));
	p = (String*)malloc(sizeof(String));
	size_ss = LengthCHAR(ss);
	size_pp = LengthCHAR(pp);
	strcpy_s(s->chs, size_ss+1  ,ss);  //加一的目的是字符串的结尾有一个'\0'
	strcpy_s(p->chs, size_pp+1 ,pp);   //加一的目的是字符串的结尾有一个'\0'
	s->length = LengthCHAR(ss);
	p->length = LengthCHAR(pp);
	PrintString(s);
	PrintString(p);
	Fail(*p, f);
	printf("%d\n", IndexKMP(*s, *p, 0));
	printf("*************\n");
}