In the function round of Display 3.6, which of these explains what happens in the body of the function? We reproduce the one line from the function body here:

Question

```
return static_cast(floor(number+0.5));
```

a) This is overkill, it would be sufficient to use the floor function alone.
b) Adding 0.5 to number pushes the range up so floor can produce the correct rounding.
c) The static_cast is used because floor returns a double. If the double value were returned, there would be at least a warning of a double to int conversion in returning the value.
d) This is wrong. The argument for the floor function should be number-0.5.

Answer 1

b) Adding 0.5 to number pushes the range up so floor can produce the correct rounding., and c) The static_cast is used because floor returns a double. If the double value were returned, there would be at least a warning of a double to int conversion in returning the value.

Numbers between floor(number)+0.5 and floor(number)+1 should round to floor(number)+1. The expression number+0.5 pushes numbers in the range floor(number) and floor(number)+0.5 up so floor will produce the correct rounded number. It pushes numbers between floor(number) and floor(number)+0.5 to floor(number)+0.5 up but leaves them so that floor will produce the correct rounded value, namely floor(number).