Ex6.3.1

#include <stdio.h>
#include <string.h>

#define PRICE_NORMAL 7
#define PRICE_WEEKEND 10
#define DISCOUNT_CHILD 0.5
#define DISCOUNT_OLD 0.3

typedef enum { SUN,
           MON,
           TUE,
           WED,
           THU,
           FRI,
           SAT } WeekDay;
typedef enum { CHILD,
            ADULT,
            SENIOR,
            INVALID = -1
} Class;

void strupr1 (char* str) {
    for (int i=0; str[i] != '\0'; ++i) {
        if (str[i] >= 'a' && str[i] <= 'z') {
            str[i] -= 32;
        }
    }
    return;
}

int main () {
  WeekDay day;
  int age1, age2, age3, n;
  char movie1[30], movie2[30], movie3[30];
  printf("What day is it today?\n(%d=SUN, %d=MON, %d=TUE, %d=WED, %d=THU, %d=FRI, %d=SAT): ",
     SUN, MON, TUE, WED, THU, FRI, SAT);
  scanf("%d", &day);
  printf("How many people of you? ");
  scanf("%d", &n);
  if (n >= 1) {
    printf("\n\nPlease enter the age of the 1st people: ");
    scanf("%d", &age1);
    age1 = age1 >= 0 ? (age1 >= 18 ? (age1 >= 65 ? SENIOR : ADULT) : CHILD) : -1;
    if (age1 == INVALID)
        printf("Your value you enterd is invalid.\n");
    printf("What movie would you want: ");
    while (getchar() != '\n');
    scanf("%[^\n]", movie1);
    strupr1(movie1);
  }
  if (n >= 2) {
    printf("\nPlease enter the age of the 2nd people: ");
    scanf("%d", &age2);
    age2 = age2 >= 0 ? (age2 >= 18 ? (age2 >= 65 ? SENIOR : ADULT) : CHILD) : -1;
    if (age2 == INVALID)
        printf("Your value you enterd is invalid.\n");
    printf("What movie would you want: ");
    while (getchar() != '\n');
    scanf("%[^\n]", movie2);
    strupr1(movie2);
  }
  if (n>=3) {
    printf("\nPlease enter the age of the 3rd people: ");
    scanf("%d", &age3);
    age3 = age3 >= 0 ? (age3 >= 18 ? (age3 >= 65 ? SENIOR : ADULT) : CHILD) : -1;
    if (age3 == INVALID)
        printf("Your value you enterd is invalid.\n");
    printf("What movie would you want: ");
    while (getchar() != '\n');
    scanf("%[^\n]", movie3);
    strupr1(movie3);
  }

  printf("\n%d ticket(s) for you:\n\n", n);
  if (n >= 1) {
    if (age1 != INVALID) {
        float price;
        if (day==SUN || day==SAT)
            price = PRICE_WEEKEND;
        else
            price = PRICE_NORMAL;
        if (age1 == CHILD)
            price *= (1 - DISCOUNT_CHILD);
        else if (age1 == SENIOR)
            price *= 1 - DISCOUNT_OLD;
        printf("----------------------------------------\n");
        printf("|%*s%s%*s|\n", 12, "", "TICKET & BILL", 13, "");
        printf("|%*s|\n", 38, "");
        printf("|--------------------------------------|\n");
        printf("|%-*s%-*s|\n", 10, "MOVIE:", 28, movie1);
        printf("|%*s|\n", 38, "");
        printf("|%-*s%-*s|\n", 10, "Class: ", 28, age1 == CHILD ? "Child" : (age1 == ADULT ? "Adult" : "Senior Citizen"));
        printf("|%-*s%-*s|\n", 10, "Date: ", 28, (day == SUN || day == SAT) ? "Weekend" : "Normal");
        printf("|%-*s$%-*.2f|\n", 10, "Price: ", 27, price);
        printf("|%*s|\n", 38, "");
        printf("----------------------------------------\n");
    } else
        printf("Information of the 1st people is invalid.\n");
}

 if (n >= 2) {
    if (age2 != INVALID) {
        float price;
        if (day==SUN || day==SAT)
            price = PRICE_WEEKEND;
        else
            price = PRICE_NORMAL;
        if (age2 == CHILD)
            price *= (1 - DISCOUNT_CHILD);
        else if (age2 == SENIOR)
            price *= 1 - DISCOUNT_OLD;
        printf("\n----------------------------------------\n");
        printf("|%*s%s%*s|\n", 12, "", "TICKET & BILL", 13, "");
        printf("|%*s|\n", 38, "");
        printf("|--------------------------------------|\n");
        printf("|%-*s%-*s|\n", 10, "MOVIE:", 28, movie2);
        printf("|%*s|\n", 38, "");
        printf("|%-*s%-*s|\n", 10, "Class: ", 28, age2 == CHILD ? "Child" : (age2 == ADULT ? "Adult" : "Senior Citizen"));
        printf("|%-*s%-*s|\n", 10, "Date: ", 28, (day == SUN || day == SAT) ? "Weekend" : "Normal");
        printf("|%-*s$%-*.2f|\n", 10, "Price: ", 27, price);
        printf("|%*s|\n", 38, "");
        printf("----------------------------------------\n");
    } else
        printf("Information of the 2nd people is invalid.\n");
}

 if (n >= 3) {
    if (age3 != INVALID) {
        float price;
        if (day==SUN || day==SAT)
            price = PRICE_WEEKEND;
        else
            price = PRICE_NORMAL;
        if (age3 == CHILD)
            price *= (1 - DISCOUNT_CHILD);
        else if (age3 == SENIOR)
            price *= 1 - DISCOUNT_OLD;
        printf("\n----------------------------------------\n");
        printf("|%*s%s%*s|\n", 12, "", "TICKET & BILL", 13, "");
        printf("|%*s|\n", 38, "");
        printf("|--------------------------------------|\n");
        printf("|%-*s%-*s|\n", 10, "MOVIE:", 28, movie3);
        printf("|%*s|\n", 38, "");
        printf("|%-*s%-*s|\n", 10, "Class: ", 28, age3 == CHILD ? "Child" : (age3 == ADULT ? "Adult" : "Senior Citizen"));
        printf("|%-*s%-*s|\n", 10, "Date: ", 28, (day == SUN || day == SAT) ? "Weekend" : "Normal");
        printf("|%-*s$%-*.2f|\n", 10, "Price: ", 27, price);
        printf("|%*s|\n", 38, "");
        printf("----------------------------------------\n");
    } else
        printf("Information of the 3rd people is invalid.\n");
}
}