Difference in C

getc and putc are standard, getch/putch and friends are not. But assuming you use a compiler where getch and friends are supported, the difference is usually as follows:

getc/putc - Works through the standard C stream framework and are not limited to the keyboard and console.
getch/putch - Works directly with the keyboard buffer/console, respectively.

Further, getch differs from getc in behavior because the C stream framework is typically line buffered (this comes from the underlying shell) and input will not be sent to the program until a newline is detected. Thus getch and getche are ways to read a single character immediately without requiring the user to press the enter key.

Finally, getch and getche differ in that getch reads a character without echoing it to the screen while getche does echo the character. getc follows the rules of the underlying shell, which usually echoes the characters being typed.