我创建了一个C程序，它将接受用户的所有订单，然后生成订单的总计。
但是当我要点其他食物时，程序会自动关闭。
我不知道这是关于我的失误还是切换方法的中断。有时，它将继续出现另一个错误，但会自动输出“ INVALID FOOD”。
这是我的代码：
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
void menu();
void foods();
void main();
char food;
int quantity;
float price;
float total;
float grandtotal;
int choice;
void main()
{
clrscr();
menu();
foods();
getch();
}
void menu(){
food = ' ';
quantity = 0;
price = 0;
total = 0;
choice = 0;
printf("Please select food from the following:\n");
printf(" B = Burger, F = French Fries, P = Pizza, S = Sandwiches \n");
printf("Enter food:");
scanf("%c", &food);
}
void foods(){
switch(food)
{
case 'B':
printf("You selected Burger!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 95.50;
printf("\n Do you want to order more? [1] Yes [2] No:");
scanf("%d", &choice);
total = price*quantity;
if(choice == 1){
menu();
break;
}
else if (choice == 2){
grandtotal = grandtotal + total;
printf("\n Total Price is: %0.2f", grandtotal);
break;
}
case 'F':
printf("You selected French Fries!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 47.75;
printf("\n Do you want to order more? [1] Yes [2] No:");
scanf("%d", &choice);
total = price*quantity;
if(choice == 1){
menu();
break;
}
else if (choice == 2){
grandtotal = grandtotal + total;
printf("\n Total Price is: %0.2f", grandtotal);
break;
}
case 'P':
printf("You selected French Pizza!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 105.00;
printf("\n Do you want to order more? [1] Yes [2] No:");
scanf("%d", &choice);
total = price*quantity;
if(choice == 1){
menu();
break;
}
else if (choice == 2){
grandtotal = grandtotal + total;
printf("\n Total Price is: %0.2f", grandtotal);
break;
}
case 'S':
printf("You selected Sandwiches\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 75.50;
printf("\n Do you want to order more? [1] Yes [2] No:");
scanf("%d", &choice);
total = price*quantity;
if(choice == 1){
main();
break;
}
else if (choice == 2){
grandtotal = grandtotal + total;
printf("\n Total Price is: %0.2f", grandtotal);
break;
}
default:
printf("INVALID FOOD!");
break;
}
}
我希望有人可以帮助或指导我。预先感谢。
答案 0 :(得分：3)
在您的代码中，您已经重复了多次：
...
if(choice == 1){
menu();
break;
} ...
...
因此，当您选择choice = 1时，会显示menu() get，然后代码会从foods()中跳出来。我认为您打算再次做“食物”部分：
...
if(choice == 1){
menu();
foods();
break;
} ...
...
代码中的另一个问题是%c scanf修饰符。它不会占用前导空格，因此它将读取换行符（在最后一个scanf上输入）。在" %c"
scanf(" %c", &food);告诉scanf读取前导空格并忽略前导换行符。
scanf(... &choice); if (choice == 1) ... else if (choice == 2)可以放在while开关的外部，不会重复4次。您的代码经过稍微修改后带有一点缩进，添加了do ... while循环并删除了全局变量和代码重复，看起来像这样：
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
char menu(void);
float foods(char food);
void main()
{
clrscr();
float grandtotal = 0;
int choice = 0;
do {
// print menu and choose the food
char food = menu();
// choose food quantity and get it's price
float total = foods(food);
// print the total price
grandtotal = grandtotal + total;
printf("\n Total Price is: %0.2f", grandtotal);
// do you want to continue?
printf("\n Do you want to order more? [1] Yes [2] No:");
if (scanf("%d", &choice) != 1) {
perror("scanf error");
abort();
}
// continue until choice is equal to 1
} while (choice != 1);
}
char menu(void)
{
char food;
printf("Please select food from the following:\n");
printf(" B = Burger, F = French Fries, P = Pizza, S = Sandwiches \n");
printf("Enter food:");
if (scanf(" %c", &food) != 1) {
perror("scanf error");
abort();
}
return food;
}
float foods(char food){
float price = 0;
switch (food) {
case 'B':
printf("You selected Burger!\n");
price = 95.50;
break;
case 'F':
printf("You selected French Fries!\n");
price = 47.75;
break;
case 'P':
printf("You selected French Pizza!\n");
price = 105.00;
break;
case 'S':
printf("You selected Sandwiches\n");
price = 75.50;
break;
default:
fprintf(stderr, "INVALID FOOD!\n");
abort();
}
printf("Enter quantity:");
int quantity;
if (scanf("%d", &quantity) != 1) {
perror("scanf error");
abort();
}
return (float)price * (float)quantity;
}
答案 1 :(得分：2)
在用户输入后调用菜单时，[1]是。使用menu（）函数显示菜单，然后在菜单之后显示调用food（）函数。
您想做什么
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
void menu();
void foods();
void main();
char food;
int quantity;
float price;
float total;
float grandtotal;
int choice;
void main()
{
clrscr();
do {
menu();
foods();
printf("\n Do you want to order more? [1] Yes [2] No:");
scanf("%d", &choice);
getchar(); // <== remove newline
grandtotal = grandtotal + total;
} while (choice == 1);
printf("\n Total Price is: %0.2f", grandtotal);
getch();
}
void menu() {
food = ' ';
quantity = 0;
price = 0;
total = 0;
choice = 0;
printf("Please select food from the following:\n");
printf(" B = Burger, F = French Fries, P = Pizza, S = Sandwiches \n");
printf("Enter food:");
scanf("%c", &food);
}
void foods() {
switch (food)
{
case 'B':
printf("You selected Burger!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 95.50;
//printf("\n Do you want to order more? [1] Yes [2] No:");
//scanf("%d", &choice);
//getchar(); // <== remove newline
total = price*quantity;
break;
//if (choice == 1) {
// menu();
// break;
//}
//else if (choice == 2) {
// grandtotal = grandtotal + total;
// printf("\n Total Price is: %0.2f", grandtotal);
// break;
//}
case 'F':
printf("You selected French Fries!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 47.75;
//printf("\n Do you want to order more? [1] Yes [2] No:");
//scanf("%d", &choice);
total = price*quantity;
break;
//if (choice == 1) {
// menu();
// break;
//}
//else if (choice == 2) {
// grandtotal = grandtotal + total;
// printf("\n Total Price is: %0.2f", grandtotal);
// break;
//}
case 'P':
printf("You selected French Pizza!\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 105.00;
//printf("\n Do you want to order more? [1] Yes [2] No:");
//scanf("%d", &choice);
total = price*quantity;
break;
//if (choice == 1) {
// menu();
// break;
//}
//else if (choice == 2) {
// grandtotal = grandtotal + total;
// printf("\n Total Price is: %0.2f", grandtotal);
// break;
//}
case 'S':
printf("You selected Sandwiches\n");
printf("Enter quantity:");
scanf("%d", &quantity);
price = 75.50;
//printf("\n Do you want to order more? [1] Yes [2] No:");
//scanf("%d", &choice);
total = price*quantity;
break;
//if (choice == 1) {
// main();
// break;
//}
//else if (choice == 2) {
// grandtotal = grandtotal + total;
// printf("\n Total Price is: %0.2f", grandtotal);
// break;
//}
default:
printf("INVALID FOOD!");
break;
}
}