Recursion is when a function calls itself again and again until it reaches a specified stopping condition.

Parts of a Recursive Function

Each recursive function has two parts:

  • Base Case: The base case is where the call to the function stops i.e., it does not make any subsequent recursive calls

  • Recursive Case: The recursive case is where the function calls itself again and again until it reaches the base case.

How do you solve a problem using recursion?

To solve a problem using recursion, break the problem into one or more smaller problems, and add one or more base conditions that stop the recursion. i.e. make a recurrence relation for that problem.

How is memory allocated to different function calls in recursion?

When a function is called, the state of that function is saved in a stack. Each recursive call pushes a new stack frame. When the base case is reached the stack frames start popping from the stack until the stack becomes empty.


The task is to calculate x power n:

For example,

if x=2 and n=3



The following code explains how to calculate x power n using recursion:

using namespace std;
//recursive function
int power(int x, int n) {
if (n == 1) { //base case
return x;
} else {
return x * power(x, n - 1);//recursive case
//driver function
int main()
int x=2;
int n=3;
cout<<x<<" ^ "<<n<<" : ";
cout<<power(2, 3);

Visualization Through the Stack

The following illustration helps to visualize the code through a stack: