关于自动机的相关问题

根据自动机的原理，我参考了一些资料，做了一个简易的c程序实现。

#include<stdio.h>
#include<string.h>
#define MAX 20
int n=1;
void tackBack(char sh[],int start,int End,int Begain,int Fin);//进行判定操作 
int main(){
    char sh[MAX];
    int size;
    scanf("%s",sh);
    size=strlen(sh);
    tackBack(sh,0,size,0,1);
    return 0;
}

void tackBack(char sh[],int start,int End,int Begain,int Fin)
{
    
    int i=start;    
    while(!(sh[i] == '|') && i<End)//如果遇到||或者到了结束 
        i++;
    if(sh[i]=='|'){
        tackBack(sh,start,i-1,Begain,Fin);//递归判定遇到|| 
        tackBack(sh,i+1,End,Begain,Fin);    
    }
    i=start;
    if(sh[i]>='a' && sh[i]<='z')//遇到的a.....z之间 
    {
        if(sh[i+1]=='.')//遇到. 
        {
            n++;
            printf("f<%d,%c>=%d
",Begain,sh[i],n);                
        }
        else if(sh[i+1]=='*')//遇到* 
        {
            n++;
            printf("f(%d,~)=%d
",Begain,n);
            printf("f(%d,~)=%d
",n,Fin);
            printf("f(%d,%c)=%d
",n,sh[i],n);
        }
    }    
    i+=2;
    while(i<End)
    {
        if(sh[i]>='a' && sh[i]<='z')
        {
            if(sh[i+1]=='.')
            {
                printf("f<%d,%c>=%d
",n,sh[i],n+1);        
                n++;
            }
            else if(sh[i+1]=='*')
            {
                n++;
                printf("f(%d,~)=%d
",Begain,n);
                printf("f(%d,~)=%d
",n,Fin);
                printf("f(%d,%c)=%d
",n,sh[i],n);
            }
        }    
        i++;
    }
    if(sh[i]>='a' && sh[i]<='z')
    {
        
        if(sh[i+1]=='*')
        {
            printf("f(%d,%c)=%d
",n,sh[i],Fin);
        }
        else
        {
            printf("f<%d,%c>=%d
",n,sh[i],Fin);
        }
    }

}