Find the error(s) in each of the following program segments, and explain how the error(s) can be corrected :

```
int sum(int n) { // assume n is nonnegative if (0 == n)
return 0;
else
n + sum(n - 1);
}
```

Error: The result of n + sum(n - 1) is not returned; sum returns an improper result.
Correction: Rewrite the statement in the else clause as
```
return n + sum(n - 1);
```