try_define

いかをコピーして、プログラムをつくりましょう。

#include <stdio.h>

#define M1  "HAM EGG"  //menu No.1 assigned
#define M1P 200        //menu No.1 price

int main(void)
{
    int order;
    int q;
    int M1q=0;

do {
        printf("\n-----MENU------\n");
        printf("1. %s %d yen.\n",M1,M1P); //use M1, M1P 
        printf("2. SOUSAGE  100 yen.\n");
        printf("3. HOT DOG  300 yen.\n");
        printf("0. END.\n");

printf("\nselect order No. ----> ");
        scanf("%d", &order);

if (order >= 1 && order <= 3) {
            printf("\nhow many ----> ");
            scanf("%d", &q);

printf("\n");

switch (order) {
            case 1: printf("%s %d, %d yen\n\n", M1,q, q * M1P); //use M1, M1P
                M1q += q;
                break;
            case 2: printf("SOUSAGE %d, %d yen\n\n", q, q * 100);
                break;
            case 3: printf("HOT DOG %d, %d yen\n\n", q, q * 300);
                break;
            }
        }
        else if (order != 0){
            printf("\nselecet 1,2,3\n");
        }

printf("\x1b[2J");      //clear display
        printf("\x1b[1;1H");    //set cursol position to 1,1
 
        //display order
        printf("---- order list ----\n");
        if (M1q != 0) {
            printf("%s %d", M1, M1q);
        }
        printf("\n");

} while (order != 0);
    printf("\nthank you.\n");
    return 0;
}