好的，所以我试图建立一个基本程序来计算披萨订单的价格。我想要询问客户是否订购了。如果他们输入y然后我希望循环继续，如果输入任何其他字符我想让它停止。当我输入任何字符时，程序只是连续打印出我的所有printf语句。我正在使用代码块。这是我的代码。我得到2个警告。
warning: initialization makes integer from pointer without a cast [enabled by default] at line 17 where i declare the keepgoing variable.
warning: comparison between pointer and integer [enabled by default]|
第19行，其中while循环开始。
#include <stdio.h>
#include <stdlib.h>
main()
{
#define LARGEPIZZAPRICE
#define SMALLPIZZAPRICE
#define LARGEPIZZATOPPING
#define SMALLPIZZATOPPING
#define DRINK
int numberOfLargePizzas;
int numberOfSmallPizzas;
int numberOfLargeToppings;
int numberOfSmallToppings;
int numberOfDrinks;
int keepGoing = "y";
while (keepGoing == "y")
{
printf("How many large pizza's do you want\n");
scanf(" %d", &numberOfLargePizzas);
printf("How many large toppings do you want\n");
scanf(" %d", &numberOfLargeToppings);
printf("How many small pizza's do you want\n");
scanf(" %d", &numberOfSmallPizzas);
printf("How many small toppings do you want\n");
scanf(" %d", &numberOfSmallToppings);
printf("Would you like to order more. Enter a y or n\n");
scanf(" %i", &keepGoing);
}
}`
***** UPDATE ***** 好的，感谢所有的帮助，它现在运行良好。如果有人可以查看它并给出任何提示来收紧或做我更容易做的事情，请告诉我。这对我来说是学习经验，我通过反复试验来做到这一点。该程序运行，但我有一种感觉，我错误地构造它。这就是我所拥有的：
#include <stdio.h>
#include <stdlib.h>
main()
{
#define LARGEPIZZAPRICE 12
#define SMALLPIZZAPRICE 10
#define LARGEPIZZATOPPING 2
#define SMALLPIZZATOPPING 1.50
#define DRINK 1.50
#define TAXRATE .05
int numberOfLargePizzas;
int numberOfSmallPizzas;
int numberOfLargeToppings;
int numberOfSmallToppings;
int numberOfDrinks;
char keepGoing ='y';
float largePizzaTotal;
float smallPizzaTotal;
float drinkTotal;
while (keepGoing == 'y')
{
printf("How many large pizza's do you want\n");
scanf(" %d", &numberOfLargePizzas);
if(numberOfLargePizzas != 0){
printf("How many large toppings do you want\n");
scanf(" %d", &numberOfLargeToppings);
}
printf("How many small pizza's do you want\n");
scanf(" %d", &numberOfSmallPizzas);
if(numberOfSmallPizzas !=0){
printf("How many small toppings do you want\n");
scanf(" %d", &numberOfSmallToppings);
}
printf("How many drinks would you like\n");
scanf(" %int", &numberOfDrinks);
printf("Would you like to order more. Enter a y or n\n");
scanf(" %c", &keepGoing);
}
largePizzaTotal = (LARGEPIZZAPRICE*numberOfLargePizzas)+(LARGEPIZZATOPPING*numberOfLargeToppings);
smallPizzaTotal=(SMALLPIZZAPRICE*numberOfSmallPizzas)+(SMALLPIZZATOPPING*numberOfSmallToppings);
drinkTotal = DRINK*numberOfDrinks;
printf("Subtotal: %2f", largePizzaTotal + smallPizzaTotal + drinkTotal);
}
答案 0 :(得分：2)
您无法比较c中的字符串，可能就是
char keepGoing = 'y';
if (keepGoing == 'y')
但是你应该修复scanf()
scanf(" %c", &keepGoing);
int keepGoing = "y";
编译好，但是错误。
你的编译器确实告诉你它错了，因为int和指针是不兼容的类型。
答案 1 :(得分：0)
您正在将integer变量与character数据进行比较。
替换int keepGoing = "y";
带
char keepGoing = 'y';
并替换
while (keepGoing == "y")
while (keepGoing == 'y')
或者如果您想处理案件，请将其替换为
while ( keepGoing == 'y' || keepGoing == 'Y')
答案 2 :(得分：0)
你要求提出收紧你正在做的事情的提示。我花了一点时间，概述了围绕Pizza Shop Menu的披萨店的方法。这不是提示每个循环中有多少 - 而是在每个循环中提供一个小菜单，您可以选择L表示大，S表示小而D表示饮料，然后填写在数量上。 （菜单条目可以是大写或小写）不允许使用无效的菜单选项（不显示错误，菜单只是重新显示）
我没有等到最后总和和总数，而是更容易简单地保持每种类型的销售总额，小计，税金等。您可以比较两种方法并查看您喜欢的方式。
此外，在每个scanf输入（格式字符串不使用newline）之后，清空输入缓冲区以防止scanf出现跳过条目。如果您有任何疑问，请查看并告诉我。有许多方法可以做到这一点，没有比下一个更好的方法（只要它们是正确的）。这一切都归结为那时的品味和效率。 （注意：如果是限制，则不会包含其他标头文件，因此可以使用strchr更轻松地检查string.h等有效条目。等等。）
#include <stdio.h>
#include <stdlib.h>
/* defines are preprocessor commands that simply cause the
* preprocessor to do a global search-and-replace of the
* labels with values. They traditionally go at the top.
* You can add storage type suffixes to the numbers to
* prevent ambiguity. (e.g. F float, U unsigned, ...)
*/
#define LARGEPIZZAPRICE 12.0F
#define SMALLPIZZAPRICE 10.0F
#define LARGEPIZZATOPPING 2.0F
#define SMALLPIZZATOPPING 1.50F
#define DRINK 1.50F
#define TAXRATE .05F
/* empty input buffer after reading from stdin */
void flush_stdin ()
{
int c = 0;
while ((c = getchar()) != '\n' && c != EOF);
}
int show_menu ()
{
int c = 0;
/* quick & dirty menu */
printf ("\n Pizza Shop Menu\n\n");
printf (" L) Large Pizza\n");
printf (" S) Small Pizza\n");
printf (" D) Drink\n");
printf (" --------------------\n");
printf (" C) Checkout\n\n");
printf (" Choice: ");
c = getchar ();
flush_stdin ();
/* return only upper case letters */
return c > 'Z' ? c - 'a' + 'A' : c;
}
int main (void)
{
/* ALWAYS INITIALIZE ALL VARIABLES
* accidentally reading from an uninitialized variable
* is Undefined Behavior.
*/
int numberOfLargePizzas = 0;
int numberOfSmallPizzas = 0;
int numberOfLargeToppings = 0;
int numberOfSmallToppings = 0;
int numberOfDrinks = 0;
float price = 0.0;
float subtotal = 0.0;
float tax = 0.0;
while (1)
{
int n = 0;
switch (show_menu())
{
case 'L' :
printf ("\n How many large pizza's do you want : ");
scanf ("%d", &n);
flush_stdin ();
if (n)
{
numberOfLargePizzas += n;
price = n * LARGEPIZZAPRICE;
tax += price * TAXRATE;
subtotal += price;
n = 0;
printf (" How many large toppings do you want: ");
scanf ("%d", &n);
flush_stdin ();
if (n)
{
numberOfLargeToppings += n;
price = n * LARGEPIZZATOPPING;
tax += price * TAXRATE;
subtotal += price;
}
}
printf ("\n Subtotal : %.2f\n Tax : %.2f\n Total : %.2f\n",
subtotal, tax, subtotal + tax);
break;
case 'S' :
printf ("\n How many small pizza's do you want : ");
scanf ("%d", &n);
flush_stdin ();
if (n)
{
numberOfSmallPizzas += n;
price = n * SMALLPIZZAPRICE;
tax += price * TAXRATE;
subtotal += price;
n = 0;
printf (" How many small toppings do you want: ");
scanf ("%d", &n);
flush_stdin ();
if (n)
{
numberOfSmallToppings += n;
price = n * SMALLPIZZATOPPING;
tax += price * TAXRATE;
subtotal += price;
}
}
printf ("\n Subtotal : %.2f\n Tax : %.2f\n Total : %.2f\n",
subtotal, tax, subtotal + tax);
break;
case 'D' :
printf ("\n How many drinks would you like: ");
scanf ("%d", &n);
flush_stdin ();
if (n)
{
numberOfDrinks += n;
price = n * DRINK;
tax += price * TAXRATE;
subtotal += price;
}
printf ("\n Subtotal : %.2f\n Tax : %.2f\n Total : %.2f\n",
subtotal, tax, subtotal + tax);
break;
case 'C' :
printf ("\nOrder:\n");
printf (" ------------------------\n");
printf (" Large Pizzas : %2d\n Large Toppings : %2d\n", numberOfLargePizzas, numberOfLargeToppings);
printf (" Small Pizzas : %2d\n Small Toppings : %2d\n", numberOfSmallPizzas, numberOfSmallToppings);
printf (" Drinks : %2d\n", numberOfDrinks );
printf (" ------------------------\n");
printf (" Subtotal : %6.2f\n Tax : %6.2f\n Total : %6.2f\n",
subtotal, tax, subtotal + tax);
printf (" ------------------------\n\n");
return 0;
default:
/* uncomment to show bad menu entry */
// printf (" <--invalid entry-->\n");
break;
}
}
return 0;
}
示例：
$ ./bin/pizzas
Pizza Shop Menu
L) Large Pizza
S) Small Pizza
D) Drink
--------------------
C) Checkout
Choice: l
How many large pizza's do you want : 2
How many large toppings do you want: 2
Subtotal : 28.00
Tax : 1.40
Total : 29.40
Pizza Shop Menu
L) Large Pizza
S) Small Pizza
D) Drink
--------------------
C) Checkout
Choice: d
How many drinks would you like: 4
Subtotal : 34.00
Tax : 1.70
Total : 35.70
Pizza Shop Menu
L) Large Pizza
S) Small Pizza
D) Drink
--------------------
C) Checkout
Choice: c
Order:
------------------------
Large Pizzas : 2
Large Toppings : 2
Small Pizzas : 0
Small Toppings : 0
Drinks : 4
------------------------
Subtotal : 34.00
Tax : 1.70
Total : 35.70
------------------------