printf() and scanf() are basically used for printing output/input from all data types. However, getch(),putch(),getchar(),putchar() are specifically meant for Character/String. While printf() and scanf() are standard library functions, getch(),putch()...are contained in string.h.
printf() and scanf() has gotta do with all data types,while getchar(),putchar(),gets(),puts() only related with Character/String Input and Output. I hope the descp helps you. If it doesn't then we can go for further discussion in comments. :)