How to loop until user input N in C - c

Question

I'm a beginner in C program, and I'm trying to make a restaurant order menu.
I start with user input "Y" to start order.
Then I want the program to keep taking orders until user input "N" to stop.
When input "N", the total sales will printed.
But I cannot do the looping, would you mind to help me? Thank you. :)
#include <stdio.h>
#include <stdlib.h>
int main()
{
int code;
float totalPrice=0, totalSales = 0 ;
char choice, choice1;
printf("Welcome to Deli Sandwich! Enter Y to start your order!\n");
scanf("%c", &choice);
while(choice=='Y'|| choice=='y')
{
printf("\n____________________________SANDWICH FILLING______________________________\n");
printf("\n\t\t Menu \t\t Code \t\t Price\n");
printf("\n\t\t Egg \t\t 1 \t\t RM 1.00\n");
printf("\n\t\t Tuna \t\t 2 \t\t RM 2.00\n");
printf("\n\t\t Seafood \t 3 \t\t RM 3.00\n");
printf("\n\t\t Chicken Ham \t 4 \t\t RM 2.50\n");
printf("\nSandwich Filling code: ");
scanf("%d", &code);
switch(code)
{
case 1:
printf("Egg is picked.\n");
totalPrice+= 1;
break;
case 2:
printf("Tuna is picked.\n");
totalPrice+= 2;
break;
case 3:
printf("Seafood is picked.\n");
totalPrice+= 3;
break;
case 4:
printf("Chicken Ham is picked.\n");
totalPrice+= 2.50;
break;
default :
printf("invalid code.");
}
printf("\n_____________________________SANDWICH TYPE________________________________\n");
printf("\n\t\t Menu \t\t Code \t\t Price\n");
printf("\n\t\t Half \t\t 1 \t\t RM 3.00\n");
printf("\n\t\t Whole \t\t 2 \t\t RM 5.00\n");
printf("\nSandwich Type code: ");
scanf("%d", &code);
switch(code)
{
case 1:
printf("Half is picked.\n");
totalPrice+= 3;
break;
case 2:
printf("Whole is picked.\n");
totalPrice+= 5;
break;
default :
printf("invalid code.");
}
printf("\nThe total price is RM%.2f.\n", totalPrice);
printf("Thank You. Please come again!\n");
totalSales+= totalPrice;
printf("\nWelcome to Deli Sandwich! Enter Y to start your order!\n");
scanf("%c", &choice);
}
printf("\nThe total sales is RM%.2f.\n", totalSales);
return 0;
}
Thank you again :)

Answer 1

Change
scanf("%c", &choice);
to
scanf(" %c", &choice); // note the space before %c
This is done to discard all white-space characters like \n and spaces from the stdin.
When you enter data for a scanf,you enter some data and press the enter key. scanf consumes the data entered and leaves the \n(enter key) in the input buffer(stdin). When scanf with a %c is called the next time, it will take the \n as input(left over by the previous scanf) and will not wait for further input.
In your code,
scanf("%c", &choice);
before the while loop consumes the character you entered and leaves the \n in the stdin. As for why
scanf("%d", &code);
waits for input is that the %d format specifier skips white-space characters while %c does not.

Answer 2

scanf(" %c", &choice);
Ignore the newline character at the end of the input by placing a space before %c

Answer 3

simple add the space before %c

Answer 4

The ENTER key press after providing the input is stored into the input buffer stdin and considered a valid input for %c format specifier for the recurring scanf()s. To avoid scanning the stored \n, you need to change your code like
scanf(" %c", &choice);
^
|
This leading space indicates to ignore any leading whitespace or whitespace-like characters (including \n) and scan the first non-whitespace character. [In your case y/ Y/ n...]