Recursion is what it's called when a function calls itself. When a function calls itself immediately before returning, it's called tail recursion. Tail recursion can be more efficiently written as iteration. In fact a good compiler will recognize tail recursion and compile it as iteration.

There is no such thing as left or right recursion in C programming.

Recursion in c language is a method where the function calls itself, within or outside the scope. Using Recursion, complicated problems can be divided into smaller parts so that solving them becomes more manageable.

The recursion technique is available in Java, JavaScript, and C++.serves the same purpose.

The type of Recursion in C

• Direct Recursion

• Indirect Recursion.

Direct Recursion

Recursion can call the function n-number of times. In the case of direct Recursion, the function calls itself inside the same position or in the local scope

Direct Recursion problems are the Fibonacci series, a program to print 50 natural numbers.

Indirect Recursion

In the case of Indirect Recursion, a function X calls function Y, and function Y calls any function Z. Under certain conditions, function Z calls function A. In this case, function A is indirectly related to function Z. Indirect Recursion is also known as mutual Recursion, as more than one function runs a program. It is a two-step recursive function call process for making a recursive function call.

Below mentioned are also type of Recursion:

Tail Recursion

No Tail/Head Recursion

Linear Recursion

Tree Recursion

Tail Recursion A function is said to be tail recursion if it calls itself and also calls the last or the previous statement executed in the process.

Head Recursion A function is said to be Head Recursion if it calls itself and also calls the first or the beginning statement executed in the process.

Linear Recursion A function is said to be a linear recursive function if it makes a single call to itself each time the procedure executes itself and grows linearly depending on the size of the problem.

Tree Recursion

Tree Recursion is different from linear Recursion. Rather than making only one call to itself, that function makes more than one recursive call to the process within the recursive function.

Following are the steps to solve the recursive problem in C:

Step 1: Create a function and assign the work a part should do.

Step 2: Select the subproblem and assume that the function already works on the problem. Step 3: Get the answer to the subproblem and use it to resolve the main issue.

Step 4: The 90% of the problem defined is solved.

These terms are found in Recursion.1.Base Case:it is the case in recursion where the answer is known,or we can say the termination condition for a recursion to unwind back.For example to find Factorial of num using recursion:

int Fact(int num){

if(num==1 num==0)//base casereturn 1;else // recursive case: return num*Fact(num-1);}

2.Recursive case:It is the case whcih brings us to the closer answer.

Run Time Stack:It is a system stack us to save the frame stack of a function every recursion or every call.This frame stack consists of the return address,local variables and return value if any.

Tail Recursion:The case where the function consist of single recursive call and it is the last statement to be executed.A tail Recursion can be replace by iteration. The above function consists of tail recursion case.where as the below function does not.

void binary(int start,int end,int el){int mid;if(end>start){mid=(start+end)/2;if(el==ar[mid])return mid;else{if(el>ar[mid])binary(mid+1,end,ele);elsebinary(start,mid-11,ele);

Read the part in your programming manual/text book about recursion.

The short answer while easy does not tell you anything about the power or dangers of recursion. It is the power and dangers of recursion that is important because once understood you can use recursion to good effect without running out of stack space.

When a function calls itself it is called as direct recursion.

A function calls other functions which eventually call the original function is called as indirect recursion.