129-有确定性的有穷自动机

#include <stdio.h>  //s为初态，z为终态
int in(int s,int z)
{
    if(s == z)
    {
        printf("3\nlook!the last status belongs to Z");
        return 1;
    }
    else
    {
        return 0;
    }
} //s为状态，t为输入的字符
int step(int s,char t)
{
    if(t == ‘a‘)
        switch(s)
    {             case 0:return 1;
            case 1:return 3;
            case 2:return 1;
            case 3:return 3;
    }
    else if(t == ‘b‘)
        switch(s)
    {
             case 0:return 2;
             case 1:return 2;
             case 2:return 3;
             case 3:return 3;
    }
}
int realize(char *input)
{
    int z = 3; 

    int s,i;   

    s = 0;  

    for(i=0;input[i]!=‘\n‘;i++)
    {
        printf("%2d",s);

        s = step(s,input[i]);
    }
    if(in(s,z))
    {
        return 1;
    }
    else
    {
        return 0;

    }
}
main() {
    int i;
    int a;
    char input[40];
    printf("FA=({0,1,2,3},{a,b},M,0,{3})\n");
    printf("M:\n");
    printf("    M(0,a)=1    M(0,b)=2\n");
    printf("    M(1,a)=3    M(1,b)=2\n");
    printf("    M(2,a)=1    M(2,b)=3\n");
    printf("    M(3,a)=3    M(3,b)=3\n");
    printf("请输入你要检查的串");
lop:
    for(i=0;input[i-1] != ‘\n‘;i++)
    {
        scanf("%c",&input[i]);
    }
    for(i=0;input[i-1]!=‘\n‘;i++)
    {
        if(input[i] != ‘a‘&&input[i] != ‘b‘&&input[i] != ‘\n‘)
        {
            printf("input error,enter again please:\n");
            goto lop;
        }
    }         printf("the status sequence is :\n");
    a = realize(input);
    if(a == 1)
        printf("\nSo this string can be identified\n");
    else
        printf("\nSo this string can‘t be identified\n");
    printf("press enter to exit the program\n");
    getchar();
}