Finite State Machine Program Example (ECE 2534), C (gcc)

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// Example Finite State Machine (FSM) program example

#include <stdio.h>

// When turning in your code for HW 3, only include from here...
//----------------- START CUT HERE -----------------------------

// My states
typedef enum states {STATE_INIT, STATE_A, STATE_B, STATE_EXIT} State;

// My transitiion functions
State computeTransitionFromStateA(int value) {
    State returnState = STATE_A;
    if (value==1) {
        returnState = STATE_B;
    }
    return(returnState);
}

State computeTransitionFromStateB(int value) {
    State returnState = STATE_B;
    if (value==2) {
        returnState = STATE_A;
    } else if (value==(-1)) {
        returnState = STATE_EXIT;
    }
    return(returnState);
}

// My finite state machine
State finiteStateMachine(int num)
{
    static State systemState = STATE_INIT;
    switch (systemState) {
        case STATE_INIT:
            systemState = STATE_A;
            break;
        case STATE_A:
            systemState = computeTransitionFromStateA(num);
            break;
        case STATE_B:
            systemState = computeTransitionFromStateB(num);
            break;
        default:
            printf("Should never get here!\n");
            exit(0);
    }
    return(systemState);    
}

//----------------- END CUT HERE -----------------------------
// When turning in your code for HW 3, end code you include here...

int main(void)
{
    unsigned int inputNumber; // number that we read in from stdin
    State returnState; // new state returned by FSM
    int returnValueScanf;

printf("\n*** Finite state machine program example ***\n\n");
    
    while(1) {
    
        // Read in next integer
        returnValueScanf = scanf("%d\n", &inputNumber);
        
        // check to see if input ended
        if (returnValueScanf < 1) {
            printf("Exiting because of EOF\n");
            exit(-1);
        }
    
        // print out the input number
        printf("Read in the value %d.   ", inputNumber);
    
        // call the FSM
        returnState = finiteStateMachine(inputNumber);
        
        // Print out the result
        printf("Returned FSM state is %d.\n", returnState);
        
        // exit if STATE_D
        if (returnState == STATE_EXIT) {
            printf("Exiting\n");
            exit(0);
        }
    }
    
    return 0;
}

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Compilation time: 0.12 sec, absolute running time: 0.14 sec, cpu time: 0 sec, memory peak: 3 Mb, absolute service time: 0,35 sec