C Programming - Functions - Discussion

Hi
See this code
if(n!=0)
{
1. d = n%10;
2. n = n/10;
3. s = d+sumdig(n);
}

In 1. the value of d became 3 //remainder
In 2. the value of n became 12 //quotient
In 3. the value of s became 3+0 //initially sumdig(n)=0
Again
In 1. the value of d became 2
In 1. the value of d became 1
In 2. the value of n became 0 // 1/10=0
In 3. the value of s became 1+5
The condition false the control come to end of function

@Teja. You make a small mistake.

In first executing loop you have written that sumdig (n) =0;.

Why it is zero. ?

It is not zero. It will execute sumdig (n) function again.

Very nice vivek.

Here in this program this function (sumdig(123)) will be continue .it is nothing but the recursion function here we are using .
So
if(n!=0)
{
here n=123, 2nd loop n=12,3rd loop n=1, 4th loop =0 then the condition break;
s=d+sumdig(n) , lst time .3+2,5+1=6;

Actually u people are missing a small thing... the output is 3+2+1+0. as the return 0 is in else part which comes when if(n!=0) becomes false and then it return s. I hope everything will be clear now. :)

First d=3 and n=12.

Next d=2 and n=1.

Next d=1 and n=0.

Therefore answer is 3+2+1=6.

@ Auto Variable Initialization

S value is initialized with Garbage value.

But, this value is over written with s=d+sumdig(N);

Initially n,d contains garbage value,

step-1-> N(start)=123 D=3 N=12 S=3+step2
step-2-> N(start)=12 D=2 N=1 S=2+step3
step-3-> N(start)=1 D=1 N=0 s=1+step4
step-4-> If condition is violated return 0.

So, while returning.

step-4=0
s=1+step4 becomes 1 which is step3
s=2+step3 becomes 3 which is step2
s=3+step2 becomes 6 which is returned to main.

d%10 gives the last number of a given number i.e., for example for number 123 last number is 3 and n/10 gives the except last number it gives whole number i.e., for example for number last number is 3 and remaining are 12.

Like that you can solve the code.

If we have two return stmts without any condition then the first return statement is executed the next one is ignored. In the above program why the output 0 and 0 can anyone explain me.