Recursion in C++ is simply a function that calls itself that terminates when a base case is met. It’s very useful to learn how recursion for a couple of reasons.
- It’s easier to solve certain problems with recursion as the resulting code is usually shorter
- Sometimes its the only way
Displaying numbers recursively
So what’s an example of a recursive function? Let’s make one. Let’s start by creating a function that displays a number (it isn’t the best example, but it’s good enough to introduce you to recursion).
Display Function
void display
(int n
)
{
cout < < n <<
" ";
return;
}
All this function does is simply print the number passed in.
Recursive Display Function
Now let’s have this function call itself but lets decrement the value being displayed each time.
void display
(int n
)
{
cout < < n <<
" ";
display
(n
-1);
//Will call display but with (n-1)
return;
}
So let's say we executed display(10)
What would this display? It would display 10 9 8 7 6 5 4...and would never stop. Why? We never told the function when to terminate. This will either cause your program to run until you kill it, or may cause it to segmentation fault. In order to fix this, this calls for the addition of base case. Read more »
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