## 3.1. The alternative 

### The if structure
```Ocaml
if cond then expr1 else expr2
```
> ⚠️ `expr1` and `expr2` have to be the same type. `cond` is a `bool`

**For exemple**
```Ocaml
# if 1<2 then "higher" else "lower" ;;
-: string = "higher"

# let abs(x) = 
	if x>0 then x
	else -x ;;;

```