reading a char

[Zoiddani]

Hi all,
I am pretty new to C programming, I used Pascal before.
I've tried to write a program which converts between Fahrenheit and Celsius.
But when I ask the user to write a char, the program doesnt recognize it. I did a simple test, and I found, that my program saves the enter (\n) as well as the char. But that's not supposed to be. So how to solve this?
I used Borland C++ Builder.
Thanks for any help!

#include <stdio.h>

int main (void)
{
  char CorFahr;
  float convertable;
  printf("Convert celsius or fahrenheit? c-f");
  do
  {
	CorFahr=getchar();
	printf("%c",CorFahr);
	if (CorFahr == 'c' || CorFahr == 'f') 
	{
	printf("write c or f");
        }
  }
  while (CorFahr != 'c' || CorFahr != 'f');
  scanf("%f",&convertable);
  if (CorFahr == 'c' )
  {
    printf("%f in celsius: ",convertable);
	convertable-=32;
	convertable*=5/9;
	printf("%f\n", convertable);
  }
  if (CorFahr == 'f')
  {
	printf("%f in fahrenheit: ",convertable);
	convertable*=9/5;
	convertable+=32;
	printf("%f\n",convertable);
  }
  return 0;
}

[Bayint Naung]

fflush vs gets
I think you should read/find the c-faq before posting question.
Because this kind of question are very common.....like once a week at least...

[Zoiddani]

EDIT: Solved!

[Adak]

After each scanf(), add a getchar() line of code, to remove the newline char that scanf() leaves behind (in the keyboard buffer).

Especially needed for char input, with scanf().

[Zoiddani]

with fflush?
I got another problem now.
If I enter for example 1233 for the char, the while loop will check it 4 times (bcos its 4 chars long), if it has got an 'f' or 'c' in it. I dont understand why, because its just a char, and it should only store 1 character, not 4...

[Elysia]

You enter a string. The string is written to the input buffer.
getchar reads one character from the string and returns. If the char is not c or f, you loop until you find such a character.

[Zoiddani]

ah.. now i understand.
So how to get rid of the other characters?

[Elysia]

Depends on how you want your program to behave.
Consider the scenarios that user enters invalid input (not c or f). What do you do then?

Also, don't edit out your posts after getting an answer. Your problems might help someone else another day.

[Zoiddani]

I edited the first post because i was missing two }'s in my code.
I edited my second one, because I wrote questions, but ~2 minutes after posting I found the answer for the questions, I dont wanted to bother you

So actually, at one time theres only one character stored in my char variable.
So I don't know how long the text will be, which the user gives.
Maybe I could read the last line from stdin, check if the second character is \n or not. Is this possible?

[Elysia]

Aye, sure.
Use fgets to read into a char array.
Then you use the index operator to access a specific char.
For example:

char buf[1024];
fgets(buf, sizeof(buf), stdin);
if (buf[1] == '\n') // Arrays are 0-indexed.
    /* Do something */;

[Zoiddani]

Thanks!