C Programming - Strings - Discussion

Discussion Forum : Strings - Find Output of Program (Q.No. 6)
6.
What will be the output of the program If characters 'a', 'b' and 'c' enter are supplied as input?
#include<stdio.h>

int main()
{
    void fun();
    fun();
    printf("\n");
    return 0;
}
void fun()
{
    char c;
    if((c = getchar())!= '\n')
        fun();
    printf("%c", c);
}
abc abc
bca
Infinite loop
cba
Answer: Option
Explanation:

Step 1: void fun(); This is the prototype for the function fun().

Step 2: fun(); The function fun() is called here.

The function fun() gets a character input and the input is terminated by an enter key(New line character). It prints the given character in the reverse order.

The given input characters are "abc"

Output: cba

Discussion:
31 comments Page 2 of 4.

RAJESH KUMAR said:   9 years ago
Yes, you are right! @Amandeep I also have this confusion.

Amandeep said:   9 years ago
I'm not getting this. Once we press enter the if statement is not satisfied hence it should execute the printf statement and print the last char entered and that's it. There is no further call to the function. How can it print it in reverse order? please somebody explain me.

Manisha said:   9 years ago
In order to understand it clearly, we can break this program as below (considering input as abc)

void fun()
{
char c;
if((c = getchar())!= '\n')
{
char c;
if ((c = getchar())!= '\n')
{
char c;
if ((c = getchar())!= '\n')
{
..
}
else
{
printf("%c", c);
}
}
else
{
printf("%c", c);
}

}
else
{
printf("%c", c);
}

}

Deepak Chauhan said:   10 years ago
@Vasuveer singh what you wrote is theoretically correct but here after asking for a character again it is asking for character.

Hence after 'a' is typed and enter key is pressed it will take enter ='\0' as input for next character and will exit the loop.

Pravas said:   10 years ago
Answer is cba because, in the loop if((c=getchar()!="\n").

That means output character should not c ="\n" that is a (c!=a), so, first c is printed then b then a.

Anshul Jain said:   10 years ago
I run this program in turbo c++.

My answer is (null).

Any one explain me?

Vasuveer singh said:   1 decade ago
Hello friend,

At the very beginning the input is "a" so condition holds true hence it creates the first recursive call.

Now the input is "b" so condition holds true hence it creates the second recursive call.
Now the input is "c" so condition holds true hence it creates the third recursive call.

Now the input is "enter" so condition holds false hence it do not creates the recursive call but goes to print command, which prints "c".

Now control goes back to 2nd call of fun() in which c = 'b'.
Now control goes back to 1st call of fun() in which c = 'a'.

Durai said:   1 decade ago
How come 'char c' prints three characters continuously as array?

Bhargav said:   1 decade ago
Why void fun() is declared inside the main ?

Sony Sharma said:   1 decade ago
I am not understanding this prblm.

@Navdeep Jain can you please explain it more? Why we are only giving a, b and c as input. We can give other alphabets also.

And which part of code is working as stack?


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