#include<stdio.h>
#include<math.h>

void main()
{
    int f;
    while (1) {
        printf("Input the number of task: \n");
        printf("1. Price of the products.\n");
        printf("2. Optimal weight.\n");
        printf("3. Price with sales.\n");
        printf("4. Middle meaning.\n");
        printf("5. Exit.\n");
        scanf_s("%d", &f);
        printf("\n");
        switch (f) {
        case 1:
            int count_notebooks, price_notebook, count_pencils, price_pencil;

            printf("Input the amount of the notebooks: ");
            scanf_s("%d", &count_notebooks);
            printf("Input the price of the notebooks: ");
            scanf_s("%d", &price_notebook);
            printf("Input the amount of the pencils: ");
            scanf_s("%d", &count_pencils);
            printf("Input the price of the pencils: ");
            scanf_s("%d", &price_pencil);
            printf("Total price: %d. Please, cash ur order. \n", (count_notebooks * price_notebook) + (count_pencils * price_pencil));
            printf("\n");
            break;

        case 2:
            int your_height, your_weight, optimal_weight;
            printf("Input ur weight: ");
            scanf_s("%d", &your_weight);
            printf("Input ur height: ");
            scanf_s("%d", &your_height);
            optimal_weight = (your_height - 110) * 1.15;
            if (your_weight > optimal_weight) printf("You need to lose ur weight\n");
            else printf("You need to get fat\n");
            printf("\n");
            break;

        case 3:
            int purchase_amount;
            float aftersale1, aftersale2;
            printf("Input ur purchase amount: ");
            scanf_s("%d", &purchase_amount);
            aftersale1 = purchase_amount - (purchase_amount * 3 / 100);
            aftersale2 = purchase_amount - (purchase_amount * 5 / 100);
            if (500 <= purchase_amount <= 1000) printf("Your sale is 3.\nThe price after sale: %.3f\n", aftersale1);
            else if (purchase_amount >= 1000) printf("Your sale is 5.\nThe price after sale: %.3f\n", aftersale2);
            else printf("You do not have sales");
            printf("\n");
            break;

        case 4:
            int a, n, sum;
            float sr;

            sum = 0;
            n = 0;

            printf("Input 9999 to end the program. \n");
            printf("Input ur numbers: ");



            do {
                scanf_s("%d", &a);

                if (a > 0) {
                    sum += a;
                    n++;
                }

            } while (a != 9999);

            n--;
            sum -= a;
            sr = sum / n;
            printf("Middle meaning: %3.2f. \n", sr);

        case 5:
            return; break;

        default: printf("Unknown meaning");
            printf("\n");
        }
    }


}