I need help modifying current state machine to open lock with a specific combination

[Charak]

I need help to have this state machine open the lock with a combination of 4712


#include <stdio.h>
#include <stdlib.h>

#define NoneRight 0
#define OneRight 1
#define TwoRight 2
#define Open 3

//prototypes
void LockStateMachine(unsigned char NewEvent);
void OpenLock(void);
void LatchLock(void);

int main(int argc, char *argv[])
{
    unsigned char KeyReturn;
    while(1)
    {
            printf("Enter a number: ");
            scanf("%c", &KeyReturn); /*check for events */
            getchar();
            LockStateMachine(KeyReturn); /* run state machine */
    }
  system("PAUSE");	
  return 0;
}

void LockStateMachine(unsigned char NewEvent)
{
     static unsigned char CurrentState;
     unsigned char NextState;
     switch(CurrentState)
     {
                         case NoneRight :
                              switch(NewEvent)
                              {
                         case '2':
                              NextState = OneRight;
                              break;
                         default: /* we are already in NoneRight */
                                  break;
                               }
                               break;
                               case OneRight :
                               switch(NewEvent)
                               {
                         case '1':
                              NextState = TwoRight;
                              break;
                         default: /* anything else sends us back */
                                  NextState = NoneRight;
                                  break;
                                   }
                                   break;
                                   case TwoRight :
                                   switch(NewEvent)
                                   {
                         case '8':
                              NextState = Open;
                              OpenLock();
                              break;
                         default:
                                 NextState = NoneRight;
                                 break;
                         }
                         break;
                         case Open :
                         NextState = NoneRight;
                         LatchLock();
                         break;
     }
     CurrentState = NextState;
     return;
}
void OpenLock(void)
{
     printf("Lock opened\n");
}

void LatchLock(void)
{
     printf("Lock closed\n");
}

[rogster001]

Is it your own code? Where do you have difficulty, with your code?

[Charak]

#include <stdio.h>
#include <stdlib.h>

#define NoneRight 0
#define OneRight 1
#define TwoRight 2
#define ThreeRight 3
#define Open 4

//prototypes
void LockStateMachine(unsigned char NewEvent);
void OpenLock(void);
void LatchLock(void);

int main(int argc, char *argv[])
{
    unsigned char KeyReturn;
    while(1)
    {
            printf("Enter a number: ");
            scanf("%c", &KeyReturn); /*check for events */
            getchar();
            LockStateMachine(KeyReturn); /* run state machine */
    }
  system("PAUSE");	
  return 0;
}

void LockStateMachine(unsigned char NewEvent)
{
     static unsigned char CurrentState;
     unsigned char NextState;
     switch(CurrentState)
     {
                         case NoneRight :
                              switch(NewEvent)
                              {
                                              case '4':
                                                   NextState = OneRight;
                                                   break;
                         default: /* we are already in NoneRight */
                                  break;
                               }
                               break;
                         
                         case OneRight :
                              switch(NewEvent)
                              {
                                         case '7':
                                              NextState = TwoRight;
                                              break;
                                         default: /* anything else sends us back */
                                              NextState = NoneRight;
                                              break;
                              }
                                   
                                   break;
                         case TwoRight :
                                   switch(NewEvent)
                                   {
                                         case '1':
                                              NextState = ThreeRight;
                                              break;
                                         default: /* anything else sends us back */
                                              NextState = NoneRight;
                                              break;
                                   }
                                   
                                   break;
                         case ThreeRight :
                                   switch(NewEvent)
                                   {
                                                   case '2':
                                                        NextState = Open;
                                                        OpenLock();
                                                        break;
                                                   default:
                                                           NextState = NoneRight;
                                                           break;
                                   }
                                   break;
                         case Open :
                                   NextState = NoneRight;
                                   LatchLock();
                                   break;
     }
     CurrentState = NextState;
     return;
}
void OpenLock(void)
{
     printf("Lock opened\n");
}

void LatchLock(void)
{
     printf("Lock closed\n");
}

there, 4712, oh and the problem is that when it runs, even when I type in numbers it just keeps asking again and never actually goes to any state or opens, it compiles w/o errors :S

>>apparently currentstate is not int properly?

[Mr.777]

As your NewEvent variable has the value being passed by the main. And current state variable is locally declared and not initialized. Depending upon the compiler you are using, not sure whether it's a garbage or a zero. So,your switch statements will not even execute. You can try this with writing a default at the end of switch(current_State) or whatever the name is....


NOTE: Please read the indentation and indent your code from next time....

[Charak]

Dev C++

how do i fix currentState?

[CommonTater]

Dev C++

how do i fix currentState?

First of all if you're on DevC++ you need to update to a newer IDE and compiler.

Second... Current_State is a static variable (i.e. holds it's value between calls to the function it's in) so you can't use an initializer value on it. It's fine as it is.