C Programming - Functions - Discussion

@All.

Although It happens simultaneously, Let's understand the concept as per pre-decrement.
There is --n so first n becomes n-1 and then it goes into the recursion function....

if(n > 0)
{
fun(--n);
printf("%d,", n);
fun(--n);
}

Explained :

f(3){
n = 2

f(2){
n = 1

f(1){
n = 0

f(0){
return to f(1)
{
as per value of n of above f(1)
print(0) -> 0

return to f(2)
{
as per value of n of above f(2)
print(1) -> 1

now, n=0

f(0){
return to f(3){
as per value of n of above f(3)
print(2) -> 2

now, n=1
f(1){
n=0
f(0){
return to f(1){

as per recent value of f(1){
print(0) -> 0

now, f(0){
return

return from f(3).

So, the final answer series is 0, 1, 2, 0.

Thanks all for giving the explanation.

If you use stack concept then question contain stack key.

The Correct answer for this question is, no output. Because if the condition is true then the loop will be created. If the condition is false(n=0)it do not execute if condition. Then how control goes to printf()?

@Raj.

Your explanation is the best. Thanks.

I have a doubt when the functions are called recursively each time n value decremented by 1 hence finally it comes 0 so now n value in fun (0) is 0 so now n=0 then how it prints 1 2 in fun (1) fun (2) because here also n must be 0 how it happens? Please tell me.

Can anyone explain the program in detail?

Hi, please explain this program in simple way.

It is a stack concept.

When n=3 then it becomes 3,2,1,0 as per condition, these values are stored in the stack
0 1 2 3.

When the condition becomes false then automatically values are poped. Here top value is 0 or last inserted so 0 is first poped and execution jumps to print function and display 0 and same for all.

At last output will be;
0 1 2 0

How can I recognize a function is a recursion?

Please explain me.

Simply great @Mukunda Saini.