Why is my professor using two getchar();? [closed]

Answer 1

The best better way is not to add any code to try and keep the console window open: start your program right from the console window.

If you must start your program from the IDE and want the program to not terminate before the user presses Enter, one single getchar() should do it.

The second best better way to make the program terminate after the user presses a key, is to always make sure there are no inputs pending and use one single getchar().

The reason your teacher uses 2 getchar(), I guess, is that there is already a character in the input buffer from previous inputs. To consume all characters from the inputs, up to and including the ENTER, this is usual:

int ch;
/* ... */
printf("Press Enter"); fflush(stdout);
while ((ch = getchar()) != '\n' && ch != EOF) /* void */;