[C]: printf / scanf functions are evil

I'm just starting to learn C and the first exercise made in class was to make a program that prints the sum of two integers.

This program:

#include <stdio.h>
#include <stdlib.h>
int main (void) {
  int n1,n2;
  printf("1st int: ");
  scanf("%d",&n1);
  printf("2nd int: ");
  scanf("%d",&n2);
  printf("Sum = %d\n",n1+n2);
  return EXIT_SUCCESS;
}

I showed it to some of my older classmates and went batshit insane with it saying: DO NOT USE PRINTF AND SCANF, THEY ARE NOT FUCKING SAME and other stuff.

Will someone please input on this matter?
Thank you!

>>24
But replacing printf("%s\n") with puts("%s\n") will result in correct behaviour?!