10_2_2_guess.c

/* Asks user to guess a hidden number */

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

#define MAX_NUMBER 100

/* external variable */
int secret_number;

/* prototypes */
void initialize_number_generator(void);
void choose_new_secret_number(void);
void read_guesses(void);

int main(void)
{
    char command;

    printf("Guesss the secret number between 1 and %d. \n\n", MAX_NUMBER);
    initialize_number_generator();
    do
    {
        choose_new_secret_number();
        printf("A new number has been chosen.\n");
        read_guesses();
        printf("Play again? (Y/N) ");
        scanf(" %c", &command);
        printf("\n");
    } while (command == 'y' || command == 'Y');
    
    return 0;
}

/************************************************************************************************
 * initialize_number_generator: Initiallizes the random number generator using the time of day. *
 ************************************************************************************************/

void initialize_number_generator(void)
{
    srand((unsigned) time(NULL));
}

/************************************************************************************************
 * read_guesses: Repeatedly reads user guesses and tells the user whether each guess is too low,*
 *               too high, or correst. When the guess is correct, prints the total number of    *
                 guesses and returns.
 ************************************************************************************************/
void read_guesses(void)
{
    int guess, num_guesses = 0;

    for (;;)
    {
        num_guesses++;
        printf("Enter guess: ");
        scanf("%d", &guess);
        if (guess == secret_number)
        {
            printf("You won in %d guesses!\n\n", num_guesses);
            return;
        }
            else if (guess < secret_number)
            printf("Too low; try again.\n");
        else
            printf("Too high; try again.\n");
        
    }
}

/************************************************************************************************
 *  choose_new_secret_number: Randomly selects a number between 1 and MAX_NUMBER and stores it  *
 *                            in secret_number.                                                 *
 ************************************************************************************************/
void choose_new_secret_number(void)
{
    secret_number = rand() % MAX_NUMBER + 1;
}