10
Conversion specifications
     %d: int
     %f: float
General syntax
    printf (<format string>, <value list>);
Must be one-to-one match between
    conversion specifications
    values
Number of decimal places can be controlled
   printf("The price of a taco is %.2f\n", price_of_taco);
      The price of a taco is 1.45
Multiple values
   printf("number of tacos %d, taco price %f\n", num_tacos,price_of_taco);