Simple ScanF() doesn't work in loop

[The Pentium Guy]

Hey, long time since I've browsed these forums

I have a microcontroller which I'm trying to talk to through SecureCRT on a COM port.

I have a simple loop:

char c;

//Set up UART ports...etc
while (1)
{

printf ("scanning...\n");
scanf("%c", &c);
printf ("scanned char: %c\n",c);
}

It types in "scanning..." and waits for me to type in a character, but it must be followed by a line feed (\n). Once it scans it outputs the scanned character... as planned

But on the next iteration of the loop it assumes that the same character was scanned and it outputs it again and again. It essentially skips over the scanf line. Typing a new character won't work either

Output:scanning....
Input: 1\n
Output:scannedchar: 1
scanning....
1 scanned char: 1\n
scanning.....
1 scanned char: 1

Anyone know what the deal is?

 

[Kirby]

Flush some type of buffer?

 

[Markbnj]

As I recall scanf does not flush the newline character at the end of the input string. Therefore subsequent calls to scanf will read that newline. You can use getchar() to flush that newline and then call scanf again.

 

[EagleKeeper]

fflush() or as Mark indicated above.

 

[Cerebus451]

You can also just turn off the buffering of stdin with:
setvbuf (stdin, NULL, _IONBF, 0);