Help need to understand simple simon game

Hi, This is Deva.

i am right now end of the loop chapter.

Using compiler GNU-GCC -std-gnu99

Host OS= WIN7

Almost I understood the code. But except CLOCKS_PER_SEC,

While declaring variables at the start of block.

Its time_t now = 0;

But while in the inner loop

now = clock();
seed = time(NULL);

Is there anybody can help me understanding with this code.

I have to start Arrays. After completing this. Your help will greatly appreciated.

Code:

/*Program 4.12 Simple Simon*/
#include<stdio.h>                           /*For input and output*/
#include<ctype.h>                           /*For toupper() function*/
#include<stdbool.h>                         /*For bool, true, false*/
#include<stdlib.h>                          /*For rand() and srand()*/
#include<time.h>                            /*For time() and clock()*/

int main(void)
{
    char another_game = 'Y';                /*Records if another game is to be played*/
    int correct = true;                     /*true if correct sequence entered , false otherwise*/
    int counter = 0;                        /*Number of sequences entered successfully*/
    int sequence_length = 0;                /*Number of degit in a sequence*/
    time_t seed = 0;                        /*Seed value for random number sequence*/
    int number = 0;                         /*Stores an input digit*/
    time_t now = 0;                         /*Stores current time - seed for random values*/
    int time_taken = 0;                     /*Time taken for game in seconds*/



    printf("\n To play Simple Simon, ");    /*Describe how the game is played*/
    printf("watch the screen for a sequence of digits.");
    printf("\nWatch carefully, as the digits are only displayed" "for a second! ");
    printf("\nThe computer will remove them, and then prompt you ");
    printf("to enter the same sequence.");
    printf("\nWhen you do, you must put spaces between the degits. \n");
    printf("\nGood Luck!\nPress Enter to play\n");
    scanf("%c", &another_game);


    do                                      /*One outer loop iteration is one game*/
    {
        correct = true;                     /*By default indicates correct sequence entered*/
        counter = 0;                        /*Initialize count of number of successful tries*/
        sequence_length = 2;                /*Initial length of a digit sequence*/
        time_taken = clock();               /*Record current time at start of game*/

        while(correct)                      /*Inner loop continues as long as a sequence are entered correctly*/
        {
            sequence_length += counter++%3 == 0;
                                            /*on every third successful try, increase the sequence length*/
            seed = time(NULL);
                                            /*Set seed to be the number of seconds sine Jan 1,1970*/
            now = clock();                  /*record start time for sequence*/

                                            /*Generate a sequence of numbers and display the number*/

            srand((unsigned int)seed);      /*Initialize the random sequence*/
            for(int i = 1; i <= sequence_length; i++)
                printf("%d", rand()%10);    /*Output a random digit*/

                                            /*Wait one second*/
            for(;clock() - now < CLOCKS_PER_SEC;);

                                            /*Now ouerwrite the digit sequence*/
            printf("\r");                   /*go to beginning of the line*/

            for(int i = 1; i <= sequence_length; i++)
            printf("  ");  /*Output two spaces*/

            if(counter == 1)                /*Only output message for the first try*/
                printf("\nNow you enter the sequence - don't forget" " the spaces\n");

                else
                printf("\r");               /*Back to the beginning of the line*/

                                            /*Check the input sequence of digits against the original */
            srand((unsigned int)seed);      /*Restart the random sequence*/
            for(int i = 1; i<= sequence_length; i++)
            {
                scanf("%d", &number);       /*Read an input number*/
                if(number != rand()%10)     /*Compare against random digit*/
                {
                    correct = false;        /*Incorrect entry*/
                    break;                  /*No need to check further...*/
                }

            }
            printf("%s\n", correct? "Correct!" : "Wrong!");
        }                                   /*Calculate total time to play the game in seconds*/
        time_taken = (clock() - time_taken)/CLOCKS_PER_SEC;
                                            /*Output the game score*/
        printf("\n\n Your score is %d", --counter*100/time_taken);

        fflush(stdin);

                                            /*Check if new game required*/

        printf("\nDo you want to play again(y/n)? ");
        scanf("%c", &another_game);



    }while(toupper(another_game)== 'Y');

    return 0;                               /*Returns control to the operating system*/
}