At first I want to say, that I'm a beginner and I'm just curious, why is the result in the output doubled and due what it's so.
And this is the output:Code:#include <stdio.h> int main(void) { char ch; do { printf("Enter char: \n"); ch = getchar(); if(ch == 'q') break; printf("Hello World ! \n"); } while(ch!='q'); }
Code:Enter char: a Hello World ! Enter char: Hello World ! Enter char:
When you press 'a' then <enter>, you actually put two characters in the input buffer, the 'a' and a newline. You need to flush the input buffer: Cprogramming.com FAQ > Flush the input buffer.
You also need to return 0.
1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
3. Get rid of conio.h and other antiquated DOS crap headers.
4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.
Thank you !
OK I'm curious. I am guilty of using a scanf and fflush (stdin); which everyone tells me is not good. However this program can be fixed in about .2 seconds doing it that way.
I've been playing with the FAQ method of clearing the input buffer and cannot get a smooth run of this simple program. Here is where I'm at with the other posters program:
This program will run as expected but it never breaks the loop. My guess is that's because the input buffer is clear before the do while gets to the while part so it never sees the q. How do you get around this.Code:int _tmain(int argc, _TCHAR* argv[]) { char ch; char buf[1]; do { printf ("Enter a Char: "); ch = getchar(); while ((ch = getchar()) != '\n' && ch != EOF); if (fgets(buf, sizeof(buf), stdin)) { printf ("Hello world!\n"); } }while (ch != 'q'); return 0; }
My gosh... all that just to ignore a character?
Let the thing houseclean itself.Code:do { if (ch != '\n') printf("Enter a character : "); ch = getchar(); if (ch != '\n') printf(" You entered : %c",ch); } while (tolower(ch) ! = 'q');
Whenever you get to the end of your do-while loop, ch must needs be '\n'. Did you intend to compare buf[0]? Or, if you are looking for the char that was entered, then use a different char variable.
