Unacademy Weekly Test

Question

Consider the following program, what will be the output?

#include<stdio.h>

void main()
{

    int a;
    a = printf("2>5") > printf("2<5") ? printf("2")!=printf("20")?printf("GA"):printf("2022"):10?2!=2>5?!2?40:!2!=3?50:60:70:80;
    printf("%d",a);

}

Options:

1. 50
2. 60
3. 70
4. None of These

Answer: b. 50

Comments

This portion—1)   printf("2>5") > printf("2<5") – prints 2>52<5, and isn’t a false statement so hence a true one and then printf("2")!=printf("20") is executed

2. printf("2")!=printf("20")— prints 220 and returns a value 1 as simply 2!=20.. as this is true then GA is printed and “10” is executed.
3. As 10 is executed, and it isn’t false, so 2!=2>5 is executed and 2! = 0 (as 2>5 is false, hence 0) and returns 1, hence !2 is executed next.
4. !2 returns a zero value and as it is false the next instruction executed is !2!=3.
5. !2!=3 returns a true value (1) as !2= 0 and 0!=3 hence 50 is printed… I hope this is correct, if not please correct the wrong points, thank you in advance

Answer 1

So this is a question on nested ternary operator, grouping method is used to solve:

First check the number of question mark is equal to the number of colons in the given statement, the statement is valid only if they are equal, otherwise the statement is invalid.Here in the given statement “printf("2>5") > printf("2<5") ? printf("2")!=printf("20")?printf("GA"):printf("2022"):10?2!=2>5?!2?40:!2!=3?50:60:70:80” there are 6 each, hence the statement is a valid one.

Step 1: Start from left of the statement, match the first colon symbol you come across with its nearest question mark to its left as shown in the reference below: 

and do the same for the rest of the colon symbols in the statement.

Step 2: Consider the first sub-statement “printf("2>5") > printf("2<5")”, divide the statement according the matched colon to the question mark present in the considered sub-statement.

printf function returns the number of characters printed, so here both the printf will return 3 as there are 3 characters and also “2>52<5” gets printed.

similarly the next part of the statement is considered and solved as shown below:

So, a  is evaluated to 50.

Option A is the right answer.

Comments

Appreciate your patience in solving this 🙂

---

thank you sir :)

---

Thank you for such detailed explanation :)

Answer 2

the output will be
2<52<550
whereas the value of a = 50.

Comments

Can you explain why a will be 50!

---

wrong answer

Answer 3

Ans : 2>5 2<5 50 

Explanation : a =50 

use the brackets to each ternary operator to see how they will be evaluated.