HI ! printf will print the data you ask from the program to print, like for example if you have an int a, and you have put the value 1 to it, you can write in the program printf("The value of a is: %d\n",a); %d will print the integer after the comma, and the \n will move the cursor a line down after the printing, so you'll have printed:
The value of a is: 1
scanf reads data. For example you can have scanf(“%d”,&k); if you have an int k, before that, and it will read the value of k that the user will give and put it in k.